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1. The Dark Energy Survey Image Processing Pipeline

Author: Morganson, E., Gruendl, R. A., Menanteau, F., Kind, M. Carrasco, Chen, Y. -C., Daues, G., Drlica-Wagner, A., Friedel, D. N., Gower, M., Johnson, M. W. G., Johnson, M. D., Kessler, R., Paz-Chinchón, F., Petravick, D., Pond, C., Yanny, B., Allam, S., Armstrong, R., Barkhouse, W., Bechtol, K., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Buckley-Geer, E., Covarrubias, R., Desai, S., Diehl, H. T., Goldstein, D. A., Gruen, D., Li, T. S., Lin, H., Marriner, J., Mohr, J. J., Neilsen, E., Ngeow, C. -C., Paech, K., Rykoff, E. S., Sako, M., Sevilla-Noarbe, I., Sheldon, E., Sobreira, F., Tucker, D. L., Wester, W., Morganson, E., Gruendl, R. A., Menanteau, F., Kind, M. Carrasco, Chen, Y. -C., Daues, G., Drlica-Wagner, A., Friedel, D. N., Gower, M., Johnson, M. W. G., Johnson, M. D., Kessler, R., Paz-Chinchón, F., Petravick, D., Pond, C., Yanny, B., Allam, S., Armstrong, R., Barkhouse, W., Bechtol, K., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Buckley-Geer, E., Covarrubias, R., Desai, S., Diehl, H. T., Goldstein, D. A., Gruen, D., Li, T. S., Lin, H., Marriner, J., Mohr, J. J., Neilsen, E., Ngeow, C. -C., Paech, K., Rykoff, E. S., Sako, M., Sevilla-Noarbe, I., Sheldon, E., Sobreira, F., Tucker, D. L., and Wester, W.
Abstract: The Dark Energy Survey (DES) is a five-year optical imaging campaign with the goal of understanding the origin of cosmic acceleration. DES performs a 5000 square degree survey of the southern sky in five optical bands (g,r,i,z,Y) to a depth of ~24th magnitude. Contemporaneously, DES performs a deep, time-domain survey in four optical bands (g,r,i,z) over 27 square degrees. DES exposures are processed nightly with an evolving data reduction pipeline and evaluated for image quality to determine if they need to be retaken. Difference imaging and transient source detection are also performed in the time domain component nightly. On a bi-annual basis, DES exposures are reprocessed with a refined pipeline and coadded to maximize imaging depth. Here we describe the DES image processing pipeline in support of DES science, as a reference for users of archival DES data, and as a guide for future astronomical surveys.
Published: 2018
Full Text: View/download PDF

2. The Dark Energy Survey Image Processing Pipeline

Author: Morganson, E, Gruendl, R A, Menanteau, F, Kind, M. Carrasco, Chen, Y-C, Daues, G, Drlica-Wagner, A, Friedel, D N, Gower, M, Johnson, M W G, Johnson, M D, Kessler, R, Paz-Chinchón, F, Petravick, D, Pond, C, Yanny, B, Allam, S, Armstrong, R, Barkhouse, W, Bechtol, K, Benoit-Lévy, A, Bernstein, G M, Bertin, E, Buckley-Geer, E J, Covarrubias, R, Desai, Shantanu, et al, ., Morganson, E, Gruendl, R A, Menanteau, F, Kind, M. Carrasco, Chen, Y-C, Daues, G, Drlica-Wagner, A, Friedel, D N, Gower, M, Johnson, M W G, Johnson, M D, Kessler, R, Paz-Chinchón, F, Petravick, D, Pond, C, Yanny, B, Allam, S, Armstrong, R, Barkhouse, W, Bechtol, K, Benoit-Lévy, A, Bernstein, G M, Bertin, E, Buckley-Geer, E J, Covarrubias, R, Desai, Shantanu, and et al, .
Abstract: The Dark Energy Survey (DES) is a five-year optical imaging campaign with the goal of understanding the origin of cosmic acceleration. DES performs a similar to 5000 deg(2) survey of the southern sky in five optical bands (g, r, i, z, Y) to a depth of similar to 24th magnitude. Contemporaneously, DES performs a deep, time-domain survey in four optical bands (g, r, i, z) over similar to 27 deg(2). DES exposures are processed nightly with an evolving data reduction pipeline and evaluated for image quality to determine if they need to be retaken. Difference imaging and transient source detection are also performed in the time domain component nightly. On a bi-annual basis, DES exposures are reprocessed with a refined pipeline and coadded to maximize imaging depth. Here we describe the DES image processing pipeline in support of DES science, as a reference for users of archival DES data, and as a guide for future astronomical surveys.
Published: 2018

3. The Dark Energy Survey Image Processing Pipeline

Author: Morganson, E, Gruendl, R A, Menanteau, F, Kind, M. Carrasco, Chen, Y-C, Daues, G, Drlica-Wagner, A, Friedel, D N, Gower, M, Johnson, M W G, Johnson, M D, Kessler, R, Paz-Chinchón, F, Petravick, D, Pond, C, Yanny, B, Allam, S, Armstrong, R, Barkhouse, W, Bechtol, K, Benoit-Lévy, A, Bernstein, G M, Bertin, E, Buckley-Geer, E J, Covarrubias, R, Desai, Shantanu, et al, ., Morganson, E, Gruendl, R A, Menanteau, F, Kind, M. Carrasco, Chen, Y-C, Daues, G, Drlica-Wagner, A, Friedel, D N, Gower, M, Johnson, M W G, Johnson, M D, Kessler, R, Paz-Chinchón, F, Petravick, D, Pond, C, Yanny, B, Allam, S, Armstrong, R, Barkhouse, W, Bechtol, K, Benoit-Lévy, A, Bernstein, G M, Bertin, E, Buckley-Geer, E J, Covarrubias, R, Desai, Shantanu, and et al, .
Abstract: The Dark Energy Survey (DES) is a five-year optical imaging campaign with the goal of understanding the origin of cosmic acceleration. DES performs a similar to 5000 deg(2) survey of the southern sky in five optical bands (g, r, i, z, Y) to a depth of similar to 24th magnitude. Contemporaneously, DES performs a deep, time-domain survey in four optical bands (g, r, i, z) over similar to 27 deg(2). DES exposures are processed nightly with an evolving data reduction pipeline and evaluated for image quality to determine if they need to be retaken. Difference imaging and transient source detection are also performed in the time domain component nightly. On a bi-annual basis, DES exposures are reprocessed with a refined pipeline and coadded to maximize imaging depth. Here we describe the DES image processing pipeline in support of DES science, as a reference for users of archival DES data, and as a guide for future astronomical surveys.
Published: 2018

4. The Dark Energy Survey Image Processing Pipeline

Author: Morganson, E, Gruendl, R A, Menanteau, F, Kind, M. Carrasco, Chen, Y-C, Daues, G, Drlica-Wagner, A, Friedel, D N, Gower, M, Johnson, M W G, Johnson, M D, Kessler, R, Paz-Chinchón, F, Petravick, D, Pond, C, Yanny, B, Allam, S, Armstrong, R, Barkhouse, W, Bechtol, K, Benoit-Lévy, A, Bernstein, G M, Bertin, E, Buckley-Geer, E J, Covarrubias, R, Desai, Shantanu, et al, ., Morganson, E, Gruendl, R A, Menanteau, F, Kind, M. Carrasco, Chen, Y-C, Daues, G, Drlica-Wagner, A, Friedel, D N, Gower, M, Johnson, M W G, Johnson, M D, Kessler, R, Paz-Chinchón, F, Petravick, D, Pond, C, Yanny, B, Allam, S, Armstrong, R, Barkhouse, W, Bechtol, K, Benoit-Lévy, A, Bernstein, G M, Bertin, E, Buckley-Geer, E J, Covarrubias, R, Desai, Shantanu, and et al, .
Abstract: The Dark Energy Survey (DES) is a five-year optical imaging campaign with the goal of understanding the origin of cosmic acceleration. DES performs a similar to 5000 deg(2) survey of the southern sky in five optical bands (g, r, i, z, Y) to a depth of similar to 24th magnitude. Contemporaneously, DES performs a deep, time-domain survey in four optical bands (g, r, i, z) over similar to 27 deg(2). DES exposures are processed nightly with an evolving data reduction pipeline and evaluated for image quality to determine if they need to be retaken. Difference imaging and transient source detection are also performed in the time domain component nightly. On a bi-annual basis, DES exposures are reprocessed with a refined pipeline and coadded to maximize imaging depth. Here we describe the DES image processing pipeline in support of DES science, as a reference for users of archival DES data, and as a guide for future astronomical surveys.
Published: 2018

5. The Dark Energy Survey Image Processing Pipeline

Author: Morganson, E., Gruendl, R. A., Menanteau, F., Kind, M. Carrasco, Chen, Y. -C., Daues, G., Drlica-Wagner, A., Friedel, D. N., Gower, M., Johnson, M. W. G., Johnson, M. D., Kessler, R., Paz-Chinchón, F., Petravick, D., Pond, C., Yanny, B., Allam, S., Armstrong, R., Barkhouse, W., Bechtol, K., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Buckley-Geer, E., Covarrubias, R., Desai, S., Diehl, H. T., Goldstein, D. A., Gruen, D., Li, T. S., Lin, H., Marriner, J., Mohr, J. J., Neilsen, E., Ngeow, C. -C., Paech, K., Rykoff, E. S., Sako, M., Sevilla-Noarbe, I., Sheldon, E., Sobreira, F., Tucker, D. L., Wester, W., Morganson, E., Gruendl, R. A., Menanteau, F., Kind, M. Carrasco, Chen, Y. -C., Daues, G., Drlica-Wagner, A., Friedel, D. N., Gower, M., Johnson, M. W. G., Johnson, M. D., Kessler, R., Paz-Chinchón, F., Petravick, D., Pond, C., Yanny, B., Allam, S., Armstrong, R., Barkhouse, W., Bechtol, K., Benoit-Lévy, A., Bernstein, G. M., Bertin, E., Buckley-Geer, E., Covarrubias, R., Desai, S., Diehl, H. T., Goldstein, D. A., Gruen, D., Li, T. S., Lin, H., Marriner, J., Mohr, J. J., Neilsen, E., Ngeow, C. -C., Paech, K., Rykoff, E. S., Sako, M., Sevilla-Noarbe, I., Sheldon, E., Sobreira, F., Tucker, D. L., and Wester, W.
Abstract: The Dark Energy Survey (DES) is a five-year optical imaging campaign with the goal of understanding the origin of cosmic acceleration. DES performs a 5000 square degree survey of the southern sky in five optical bands (g,r,i,z,Y) to a depth of ~24th magnitude. Contemporaneously, DES performs a deep, time-domain survey in four optical bands (g,r,i,z) over 27 square degrees. DES exposures are processed nightly with an evolving data reduction pipeline and evaluated for image quality to determine if they need to be retaken. Difference imaging and transient source detection are also performed in the time domain component nightly. On a bi-annual basis, DES exposures are reprocessed with a refined pipeline and coadded to maximize imaging depth. Here we describe the DES image processing pipeline in support of DES science, as a reference for users of archival DES data, and as a guide for future astronomical surveys.
Published: 2018
Full Text: View/download PDF

6. LIGHT CURVES OF 213 TYPE Ia SUPERNOVAE FROM THE ESSENCE SURVEY

Author: Narayan, G., Rest, A., Tucker, B. E., Foley, R. J., Wood-Vasey, W. M., Challis, P., Stubbs, C., Kirshner, R. P., Aguilera, C., Becker, A. C., Blondin, S., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Ganeshalingam, M., Garg, A., Garnavich, P. M., Hicken, M., Jha, S. W., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miknaitis, G., Pignata, G., Prieto, J. L., Riess, A. G., Schmidt, B. P., Silverman, J. M., Smith, R. C., Sollerman, Jesper, Spyromilio, J., Suntzeff, N. B., Tonry, J. L., Zenteno, A., Narayan, G., Rest, A., Tucker, B. E., Foley, R. J., Wood-Vasey, W. M., Challis, P., Stubbs, C., Kirshner, R. P., Aguilera, C., Becker, A. C., Blondin, S., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Ganeshalingam, M., Garg, A., Garnavich, P. M., Hicken, M., Jha, S. W., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miknaitis, G., Pignata, G., Prieto, J. L., Riess, A. G., Schmidt, B. P., Silverman, J. M., Smith, R. C., Sollerman, Jesper, Spyromilio, J., Suntzeff, N. B., Tonry, J. L., and Zenteno, A.
Abstract: The ESSENCE survey discovered 213 Type Ia supernovae at redshifts 0.1 < z < 0.81 between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. We assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is similar to 1%.
Published: 2016
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7. Light curves of 213 type Ia supernovae from the ESSENCE survey

Author: Narayan, G., Rest, A., Tucker, B. E., Foley, R. J., Wood-Vasey, W. M., Challis, P., Stubbs, C., Kirshner, R. P., Aguilera, C., Becker, Andrew C, Blondin, S., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Ganeshalingam, M., Garg, A., Garnavich, P. M., Hicken, M., Jha, S. W., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miknaitis, G., Pignata, G., Prieto, J. L., Riess, A. G., Schmidt, Brian, Silverman, J. M., Smith, R. C., Sollerman, J., Spyromilio, J., Suntzeff, N. B., Tonry, J. L., Zenteno, A., Narayan, G., Rest, A., Tucker, B. E., Foley, R. J., Wood-Vasey, W. M., Challis, P., Stubbs, C., Kirshner, R. P., Aguilera, C., Becker, Andrew C, Blondin, S., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Ganeshalingam, M., Garg, A., Garnavich, P. M., Hicken, M., Jha, S. W., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miknaitis, G., Pignata, G., Prieto, J. L., Riess, A. G., Schmidt, Brian, Silverman, J. M., Smith, R. C., Sollerman, J., Spyromilio, J., Suntzeff, N. B., Tonry, J. L., and Zenteno, A.
Abstract: The ESSENCE survey discovered 213 Type Ia supernovae at redshifts 0.1 < z < 0.81 between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. We assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is ∼1%.
Published: 2016

8. Erratum: Automated transient identification in the dark energy survey (AJ (2015) 150 (82))

Author: Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Da Costa, LN, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Walker, AR, Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Da Costa, LN, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, and Walker, AR
Published: 2015

9. AUTOMATED TRANSIENT IDENTIFICATION IN THE DARK ENERGY SURVEY (vol 150, 82, 2015)

Author: Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Levy, A, Bertin, E, Brooks, D, Carnero Rosell, A, Castander, FJ, da Costa, LN, Covarrubias, R, DePoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Fausti Neto, A, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Walker, AR, Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Levy, A, Bertin, E, Brooks, D, Carnero Rosell, A, Castander, FJ, da Costa, LN, Covarrubias, R, DePoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Fausti Neto, A, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, and Walker, AR
Published: 2015

10. AUTOMATED TRANSIENT IDENTIFICATION in the DARK ENERGY SURVEY

Author: Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Costa, LND, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Walker, AR, Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Costa, LND, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, and Walker, AR
Abstract: We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (2013 September through 2014 February) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factor of 13.4, while only 1.0% of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility. An implementation of the algorithm and the training data used in this paper are available at http://portal.nserc.gov/project/dessn/autoscan.
Published: 2015

11. SEARCH FOR GAMMA-RAY EMISSION FROM DES DWARF SPHEROIDAL GALAXY CANDIDATES WITH FERMI-LAT DATA

Author: Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, Miguel, Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, Stephan, Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Carnero Rosell, A., Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E., Eifler, T. F., Estrada, J., Evrard, A. E., Fausti Neto, A., Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A. R., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., Zuntz, J., Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, Miguel, Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, Stephan, Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Carnero Rosell, A., Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E., Eifler, T. F., Estrada, J., Evrard, A. E., Fausti Neto, A., Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A. R., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., and Zuntz, J.
Abstract: Due to their proximity, high dark-matter (DM) content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of DM. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with DM halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged DM annihilation cross section for these new targets. If the estimated DM content of these dSph candidates is confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for DM particles with masses less than or similar to 20 GeV annihilating via the b (b) over bar or pi(+)pi(-) channels.
Published: 2015
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12. Automated Transient Identification in the Dark Energy Survey

Author: Goldstein, D. A., D'Andrea, C. B., Fischer, J. A., Foley, R. J., Gupta, R. R., Kessler, R., Kim, A. G., Nichol, R. C., Nugent, P., Papadopoulos, A., Sako, M., Smith, M., Sullivan, M., Thomas, R. C., Wester, W., Wolf, R. C., Abdalla, F. B., Banerji, M., Benoit-Lévy, A., Bertin, E., Brooks, D., Rosell, A. Carnero, Castander, F. J., da Costa, L. N., Covarrubias, R., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., March, M., Marshall, J. L., Martini, P., Merritt, K. W., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Walker, A. R., Goldstein, D. A., D'Andrea, C. B., Fischer, J. A., Foley, R. J., Gupta, R. R., Kessler, R., Kim, A. G., Nichol, R. C., Nugent, P., Papadopoulos, A., Sako, M., Smith, M., Sullivan, M., Thomas, R. C., Wester, W., Wolf, R. C., Abdalla, F. B., Banerji, M., Benoit-Lévy, A., Bertin, E., Brooks, D., Rosell, A. Carnero, Castander, F. J., da Costa, L. N., Covarrubias, R., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., March, M., Marshall, J. L., Martini, P., Merritt, K. W., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., and Walker, A. R.
Abstract: We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (Sep. 2013 through Feb. 2014) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factor of 13.4, while only 1 percent of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility. An implementation of the algorithm and the training data used in this paper are available at http://portal.nersc.gov/project/dessn/autoscan., Comment: 24 pages, 9 figures, 4 tables v3: added link to training data / implementation
Published: 2015
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13. The Difference Imaging Pipeline for the Transient Search in the Dark Energy Survey

Author: Kessler, R., Marriner, J., Childress, M., Covarrubias, R., D'Andrea, C. B., Finley, D. A., Fischer, J., Foley, R. J., Goldstein, D., Gupta, R. R., Kuehn, K., Marcha, M., Nichol, R. C., Papadopoulos, A., Sako, M., Scolnic, D., Smith, M., Sullivan, M., Wester, W., Yuan, F., Abbott, T., Abdalla, F. B., Allam, S., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brooks, D., Rosell, A. Carnero, Kind, M. Carrasco, Castander, F. J., Crocce, M., da Costa, L. N., Desai, S., Diehl, H. T., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., Gruen, D., Gruendl, R. A., Honscheid, K., James, D. J., Kuropatkin, N., Li, T. S., Maia, M. A. G., Marshall, J. L., Martini, P., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., Walker, A. R., Kessler, R., Marriner, J., Childress, M., Covarrubias, R., D'Andrea, C. B., Finley, D. A., Fischer, J., Foley, R. J., Goldstein, D., Gupta, R. R., Kuehn, K., Marcha, M., Nichol, R. C., Papadopoulos, A., Sako, M., Scolnic, D., Smith, M., Sullivan, M., Wester, W., Yuan, F., Abbott, T., Abdalla, F. B., Allam, S., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brooks, D., Rosell, A. Carnero, Kind, M. Carrasco, Castander, F. J., Crocce, M., da Costa, L. N., Desai, S., Diehl, H. T., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., Gruen, D., Gruendl, R. A., Honscheid, K., James, D. J., Kuropatkin, N., Li, T. S., Maia, M. A. G., Marshall, J. L., Martini, P., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., and Walker, A. R.
Abstract: We describe the difference imaging pipeline (DiffImg) used to detect transients in deep images from the Dark Energy Survey Supernova program (DES-SN) in its first observing season from Aug 2013 through Feb 2014. DES-SN is a search for transients in which ten 3-deg^2 fields are repeatedly observed in the g,r,i,z passbands with a cadence of about 1 week. The observing strategy has been optimized to measure high-quality light curves and redshifts for thousands of Type Ia supernova (SN Ia) with the goal of measuring dark energy parameters. The essential DiffImg functions are to align each search image to a deep reference image, do a pixel-by-pixel subtraction, and then examine the subtracted image for significant positive detections of point-source objects. The vast majority of detections are subtraction artifacts, but after selection requirements and image filtering with an automated scanning program, there are 130 detections per deg^2 per observation in each band, of which only 25% are artifacts. Of the 7500 transients discovered by DES-SN in its first observing season, each requiring a detection on at least 2 separate nights, Monte Carlo simulations predict that 27% are expected to be supernova. Another 30% of the transients are artifacts, and most of the remaining transients are AGN and variable stars. Fake SNe Ia are overlaid onto the images to rigorously evaluate detection efficiencies, and to understand the DiffImg performance. The DiffImg efficiency measured with fake SNe agrees well with expectations from a Monte Carlo simulation that uses analytical calculations of the fluxes and their uncertainties. In our 8 "shallow" fields with single-epoch 50% completeness depth 23.5, the SN Ia efficiency falls to 1/2 at redshift z 0.7, in our 2 "deep" fields with mag-depth 24.5, the efficiency falls to 1/2 at z 1.1.
Published: 2015
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14. Constraints on the Richness-Mass Relation and the Optical-SZE Positional Offset Distribution for SZE-Selected Clusters

Author: Saro, A., Bocquet, S., Rozo, E., Benson, B. A., Mohr, J., Rykoff, E. S., Soares-Santos, M., Bleem, L., Dodelson, S., Melchior, P., Sobreira, F., Upadhyay, V., Weller, J., Abbott, T., Abdalla, F. B., Allam, S., Armstrong, R., Banerji, M., Bauer, A. H., Bayliss, M., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brodwin, M., Brooks, D., Buckley-Geer, E., Burke, D. L., Carlstrom, J. E., Capasso, R., Capozzi, D., Rosell, A. Carnero, Kind, M. Carrasco, Chiu, I., Covarrubias, R., Crawford, T. M., Crocce, M., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., de Haan, T., Diehl, H. T., Dietrich, J. P., Doel, P., Cunha, C. E, Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., Gangkofner, C., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gupta, N., Hennig, C., Holzapfel, W. L., Honscheid, K., Jain, B., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Maia, M. A. G., March, M., Marshall, J. L., Martini, Paul, McDonald, M., Miller, C. J., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Reichardt, C. L., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Schubnell, M., Sevilla, I., Smith, R. C., Stalder, B., Stark, A. A., Strazzullo, V., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Vikram, V., von der Linden, A., Walker, A. R., Wechsler, R. H., Wester, W., Zenteno, A., Ziegler, K. E., Saro, A., Bocquet, S., Rozo, E., Benson, B. A., Mohr, J., Rykoff, E. S., Soares-Santos, M., Bleem, L., Dodelson, S., Melchior, P., Sobreira, F., Upadhyay, V., Weller, J., Abbott, T., Abdalla, F. B., Allam, S., Armstrong, R., Banerji, M., Bauer, A. H., Bayliss, M., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brodwin, M., Brooks, D., Buckley-Geer, E., Burke, D. L., Carlstrom, J. E., Capasso, R., Capozzi, D., Rosell, A. Carnero, Kind, M. Carrasco, Chiu, I., Covarrubias, R., Crawford, T. M., Crocce, M., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., de Haan, T., Diehl, H. T., Dietrich, J. P., Doel, P., Cunha, C. E, Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., Gangkofner, C., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gupta, N., Hennig, C., Holzapfel, W. L., Honscheid, K., Jain, B., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Maia, M. A. G., March, M., Marshall, J. L., Martini, Paul, McDonald, M., Miller, C. J., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Reichardt, C. L., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Schubnell, M., Sevilla, I., Smith, R. C., Stalder, B., Stark, A. A., Strazzullo, V., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Vikram, V., von der Linden, A., Walker, A. R., Wechsler, R. H., Wester, W., Zenteno, A., and Ziegler, K. E.
Abstract: We cross-match galaxy cluster candidates selected via their Sunyaev-Zel'dovich effect (SZE) signatures in 129.1 deg$^2$ of the South Pole Telescope 2500d SPT-SZ survey with optically identified clusters selected from the Dark Energy Survey (DES) science verification data. We identify 25 clusters between $0.1\lesssim z\lesssim 0.8$ in the union of the SPT-SZ and redMaPPer (RM) samples. RM is an optical cluster finding algorithm that also returns a richness estimate for each cluster. We model the richness $\lambda$-mass relation with the following function $\langle\ln\lambda|M_{500}\rangle\propto B_\lambda\ln M_{500}+C_\lambda\ln E(z)$ and use SPT-SZ cluster masses and RM richnesses $\lambda$ to constrain the parameters. We find $B_\lambda= 1.14^{+0.21}_{-0.18}$ and $C_\lambda=0.73^{+0.77}_{-0.75}$. The associated scatter in mass at fixed richness is $\sigma_{\ln M|\lambda} = 0.18^{+0.08}_{-0.05}$ at a characteristic richness $\lambda=70$. We demonstrate that our model provides an adequate description of the matched sample, showing that the fraction of SPT-SZ selected clusters with RM counterparts is consistent with expectations and that the fraction of RM selected clusters with SPT-SZ counterparts is in mild tension with expectation. We model the optical-SZE cluster positional offset distribution with the sum of two Gaussians, showing that it is consistent with a dominant, centrally peaked population and a sub-dominant population characterized by larger offsets. We also cross-match the RM catalog with SPT-SZ candidates below the official catalog threshold significance $\xi=4.5$, using the RM catalog to provide optical confirmation and redshifts for additional low-$\xi$ SPT-SZ candidates.In this way, we identify 15 additional clusters with $\xi\in [4,4.5]$ over the redshift regime explored by RM in the overlapping region between DES science verification data and the SPT-SZ survey., Comment: 15 pages, 8 Figures, submitted to MNRAS
Published: 2015
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15. DESAlert: Enabling Real-Time Transient Follow-Up with Dark Energy Survey Data

Author: Poci, A., Kuehn, K., Collaboration, the DES, Abbott, T., Abdalla, F. B., Allam, S., Bauer, A. H., Benoit-Lévy, A., Bertin, E., Brooks, D., Brown, P. J., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Covarrubias, R., da Costa, L. N., D'Andrea, C. B., DePoy, D. L., Desai, S., Dietrich, J. P., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., March, M., Marshall, J., Merritt, K. W., Miller, C. J., Nichol, R. C., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla, I., Smith, C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., Walker, A. R., Wester, W., Poci, A., Kuehn, K., Collaboration, the DES, Abbott, T., Abdalla, F. B., Allam, S., Bauer, A. H., Benoit-Lévy, A., Bertin, E., Brooks, D., Brown, P. J., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Covarrubias, R., da Costa, L. N., D'Andrea, C. B., DePoy, D. L., Desai, S., Dietrich, J. P., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., March, M., Marshall, J., Merritt, K. W., Miller, C. J., Nichol, R. C., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla, I., Smith, C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., Walker, A. R., and Wester, W.
Abstract: The Dark Energy Survey (DES) is currently undertaking an observational program imaging $1/4$ of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the DES will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts (GRBs) over five years. Once GRBs are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of GRB activity, collates useful information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of GRBs, as well as for identifying key characteristics (e.g., photometric redshifts) of potential GRB host galaxies. We provide the functional details of the DESAlert software as it presently operates, as well as the data products that it produces, and we show sample results from the application of DESAlert to several previously-detected GRBs., Comment: 14 pages, 6 figures, 2 tables. Final version accepted by Publications of the Astronomical Society of Australia
Published: 2015
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16. OzDES multi-fibre spectroscopy for the Dark Energy Survey: first-year operation and results

Author: Yuan, Fang, Lidman, C., Davis, T. M., Childress, M., Abdalla, F. B., Banerji, M., Buckley-Geer, E., Rosell, A. Carnero, Carollo, D., Castander, F. J., D'Andrea, C. B., Diehl, H. T., Cunha, C. E, Foley, R. J., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A. G., King, A. L., Kuehn, K., Kuhlmann, S., Lewis, G. F., Lin, H., Martini, P., McMahon, R. G., Mould, J., Nichol, R. C., Norris, R. P., O'Neill, C. R., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A. K., Rooney, P. J., Rozo, E., Rykoff, E. S., Sako, M., Scalzo, R., Schmidt, B. P., Scolnic, D., Seymour, N., Sharp, R., Sobreira, F., Sullivan, M., Thomas, R. C., Tucker, D., Uddin, S. A., Wechsler, R. H., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A. H., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D. L., Kind, M. Carrasco, Covarrubias, R., Crocce, M., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., Marshall, J., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Walker, A. R., Yuan, Fang, Lidman, C., Davis, T. M., Childress, M., Abdalla, F. B., Banerji, M., Buckley-Geer, E., Rosell, A. Carnero, Carollo, D., Castander, F. J., D'Andrea, C. B., Diehl, H. T., Cunha, C. E, Foley, R. J., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A. G., King, A. L., Kuehn, K., Kuhlmann, S., Lewis, G. F., Lin, H., Martini, P., McMahon, R. G., Mould, J., Nichol, R. C., Norris, R. P., O'Neill, C. R., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A. K., Rooney, P. J., Rozo, E., Rykoff, E. S., Sako, M., Scalzo, R., Schmidt, B. P., Scolnic, D., Seymour, N., Sharp, R., Sobreira, F., Sullivan, M., Thomas, R. C., Tucker, D., Uddin, S. A., Wechsler, R. H., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A. H., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D. L., Kind, M. Carrasco, Covarrubias, R., Crocce, M., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., Marshall, J., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., and Walker, A. R.
Abstract: OzDES is a five-year, 100-night, spectroscopic survey on the Anglo-Australian Telescope, whose primary aim is to measure redshifts of approximately 2,500 Type Ia supernovae host galaxies over the redshift range 0.1 < z < 1.2, and derive reverberation-mapped black hole masses for approximately 500 active galactic nuclei and quasars over 0.3 < z < 4.5. This treasure trove of data forms a major part of the spectroscopic follow-up for the Dark Energy Survey for which we are also targeting cluster galaxies, radio galaxies, strong lenses, and unidentified transients, as well as measuring luminous red galaxies and emission line galaxies to help calibrate photometric redshifts. Here we present an overview of the OzDES program and our first-year results. Between Dec 2012 and Dec 2013, we observed over 10,000 objects and measured more than 6,000 redshifts. Our strategy of retargeting faint objects across many observing runs has allowed us to measure redshifts for galaxies as faint as m_r=25 mag. We outline our target selection and observing strategy, quantify the redshift success rate for different types of targets, and discuss the implications for our main science goals. Finally, we highlight a few interesting objects as examples of the fortuitous yet not totally unexpected discoveries that can come from such a large spectroscopic survey., Comment: 18 pages, 7 figures, submitted to MNRAS
Published: 2015
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17. Eight New Milky Way Companions Discovered in First-Year Dark Energy Survey Data

Author: The DES Collaboration, Bechtol, K., Drlica-Wagner, A., Balbinot, E., Pieres, A., Simon, J. D., Yanny, B., Santiago, B., Wechsler, R. H., Frieman, J., Walker, A. R., Williams, P., Rozo, E., Rykoff, E. S., Queiroz, A., Luque, E., Benoit-Levy, A., Tucker, D., Sevilla, I., Gruendl, R. A., da Costa, L. N., Neto, A. Fausti, Maia, M. A. G., Abbott, T., Allam, S., Armstrong, R., Bauer, A. H., Bernstein, G. M., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T. F., Estrada, J., Evrard, A. E., Fernandez, E., Finley, D. A., Flaugher, B., Gaztanaga, E., Gerdes, D., Girardi, L., Gladders, M., Gruen, D., Gutierrez, G., Hao, J., Honscheid, K., Jain, B., James, D., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nichol, R., Nord, B., Ogando, R., Peoples, J., Petravick, D., Plazas, A. A., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Wester, W., Zuntz, J., The DES Collaboration, Bechtol, K., Drlica-Wagner, A., Balbinot, E., Pieres, A., Simon, J. D., Yanny, B., Santiago, B., Wechsler, R. H., Frieman, J., Walker, A. R., Williams, P., Rozo, E., Rykoff, E. S., Queiroz, A., Luque, E., Benoit-Levy, A., Tucker, D., Sevilla, I., Gruendl, R. A., da Costa, L. N., Neto, A. Fausti, Maia, M. A. G., Abbott, T., Allam, S., Armstrong, R., Bauer, A. H., Bernstein, G. M., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T. F., Estrada, J., Evrard, A. E., Fernandez, E., Finley, D. A., Flaugher, B., Gaztanaga, E., Gerdes, D., Girardi, L., Gladders, M., Gruen, D., Gutierrez, G., Hao, J., Honscheid, K., Jain, B., James, D., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nichol, R., Nord, B., Ogando, R., Peoples, J., Petravick, D., Plazas, A. A., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Wester, W., and Zuntz, J.
Abstract: We report the discovery of eight new Milky Way companions in ~1,800 deg^2 of optical imaging data collected during the first year of the Dark Energy Survey (DES). Each system is identified as a statistically significant over-density of individual stars consistent with the expected isochrone and luminosity function of an old and metal-poor stellar population. The objects span a wide range of absolute magnitudes (M_V from -2.2 mag to -7.4 mag), physical sizes (10 pc to 170 pc), and heliocentric distances (30 kpc to 330 kpc). Based on the low surface brightnesses, large physical sizes, and/or large Galactocentric distances of these objects, several are likely to be new ultra-faint satellite galaxies of the Milky Way and/or Magellanic Clouds. We introduce a likelihood-based algorithm to search for and characterize stellar over-densities, as well as identify stars with high satellite membership probabilities. We also present completeness estimates for detecting ultra-faint galaxies of varying luminosities, sizes, and heliocentric distances in the first-year DES data., Comment: 33 pages, 12 figures, 3 tables. Accepted for publication in ApJ. Readers may be interested in the concurrent work by Koposov, Belokurov, Torrealba, & Evans (http://arxiv.org/abs/1503.02079). Indirect dark matter search results are presented in Drlica-Wagner, Albert, Bechtol, Wood, Strigari, et al. (The LAT and DES Collaborations, http://arxiv.org/abs/1503.02632)
Published: 2015
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18. DES13S2cmm: The First Superluminous Supernova from the Dark Energy Survey

Author: Papadopoulos, A., D'Andrea, C. B., Sullivan, M., Nichol, R. C., Barbary, K., Biswas, R., Brown, P. J., Covarrubias, R. A., Finley, D. A., Fischer, J. A., Foley, R. J., Goldstein, D., Gupta, R. R., Kessler, R., Kovacs, E., Kuhlmann, S. E., Lidman, C., March, M., Nugent, P. E., Sako, M., Smith, R. C., Spinka, H., Wester, W., Abbott, T. M. C., Abdalla, F., Allam, S. S., Banerji, M., Bernstein, J. P., Bernstein, R. A., Carnero, A., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T., Evrard, A. E., Flaugher, B., Frieman, J. A., Gerdes, D., Gruen, D., Honscheid, K., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Maia, M. A. G., Makler, M., Marshall, J. L., Merritt, K. W., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roe, N. A., Romer, A. K., Rykoff, E., Sanchez, E., Santiago, B. X., Scarpine, V., Schubnell, M., Sevilla, I., Santos, M. Soares, Suchyta, E., Swanson, M., Tarle, G., Thaler, J., Tucker, D. L., Wechsler, R. H., Zuntz, J., Papadopoulos, A., D'Andrea, C. B., Sullivan, M., Nichol, R. C., Barbary, K., Biswas, R., Brown, P. J., Covarrubias, R. A., Finley, D. A., Fischer, J. A., Foley, R. J., Goldstein, D., Gupta, R. R., Kessler, R., Kovacs, E., Kuhlmann, S. E., Lidman, C., March, M., Nugent, P. E., Sako, M., Smith, R. C., Spinka, H., Wester, W., Abbott, T. M. C., Abdalla, F., Allam, S. S., Banerji, M., Bernstein, J. P., Bernstein, R. A., Carnero, A., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T., Evrard, A. E., Flaugher, B., Frieman, J. A., Gerdes, D., Gruen, D., Honscheid, K., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Maia, M. A. G., Makler, M., Marshall, J. L., Merritt, K. W., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roe, N. A., Romer, A. K., Rykoff, E., Sanchez, E., Santiago, B. X., Scarpine, V., Schubnell, M., Sevilla, I., Santos, M. Soares, Suchyta, E., Swanson, M., Tarle, G., Thaler, J., Tucker, D. L., Wechsler, R. H., and Zuntz, J.
Abstract: We present DES13S2cmm, the first spectroscopically-confirmed superluminous supernova (SLSN) from the Dark Energy Survey (DES). We briefly discuss the data and search algorithm used to find this event in the first year of DES operations, and outline the spectroscopic data obtained from the European Southern Observatory (ESO) Very Large Telescope to confirm its redshift (z = 0.663 +/- 0.001 based on the host-galaxy emission lines) and likely spectral type (type I). Using this redshift, we find M_U_peak = -21.05 +0.10 -0.09 for the peak, rest-frame U-band absolute magnitude, and find DES13S2cmm to be located in a faint, low metallicity (sub-solar), low stellar-mass host galaxy (log(M/M_sun) = 9.3 +/- 0.3); consistent with what is seen for other SLSNe-I. We compare the bolometric light curve of DES13S2cmm to fourteen similarly well-observed SLSNe-I in the literature and find it possesses one of the slowest declining tails (beyond +30 days rest frame past peak), and is the faintest at peak. Moreover, we find the bolometric light curves of all SLSNe-I studied herein possess a dispersion of only 0.2-0.3 magnitudes between +25 and +30 days after peak (rest frame) depending on redshift range studied; this could be important for 'standardising' such supernovae, as is done with the more common type Ia. We fit the bolometric light curve of DES13S2cmm with two competing models for SLSNe-I - the radioactive decay of 56Ni, and a magnetar - and find that while the magnetar is formally a better fit, neither model provides a compelling match to the data. Although we are unable to conclusively differentiate between these two physical models for this particular SLSN-I, further DES observations of more SLSNe-I should break this degeneracy, especially if the light curves of SLSNe-I can be observed beyond 100 days in the rest frame of the supernova., Comment: Accepted by MNRAS (2015 January 23), 13 pages, 6 figures, 2 tables
Published: 2015
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19. Search for Gamma-Ray Emission from DES Dwarf Spheroidal Galaxy Candidates with Fermi-LAT Data

Author: Collaboration, The Fermi-LAT, Collaboration, The DES, Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, M., Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, S., Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., Zuntz, J., Collaboration, The Fermi-LAT, Collaboration, The DES, Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, M., Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, S., Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., and Zuntz, J.
Abstract: Due to their proximity, high dark-matter content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of dark matter. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with dark matter halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged dark matter annihilation cross section for these new targets. If the estimated dark-matter content of these dSph candidates is confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for dark matter particles with masses < 20 GeV annihilating via the b-bbar or tau+tau- channels., Comment: 9 pages, 4 figures, 1 table. Updated to published version. Readers may be interested in the related work by Ackermann et al. arXiv:1503.02641 (The Fermi-LAT Collaboration), Bechtol, Drlica-Wagner, et al. arXiv:1503.02584 (The DES Collaboration), and Koposov, Belokurov, Torrealba, & Evans arXiv:1503.02079
Published: 2015
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20. Constraints on the richness-mass relation and the optical-SZE positional offset distribution for SZE-selected clusters

Author: Saro, A, Bocquet, S, Rozo, E, Benson, BA, Mohr, J, Rykoff, ES, Soares-Santos, M, Bleem, L, Dodelson, S, Melchior, P, Sobreira, F, Upadhyay, V, Weller, J, Abbott, T, Abdalla, FB, Allam, S, Armstrong, R, Banerji, M, Bauer, AH, Bayliss, M, Benoit-Levy, A, Bernstein, GM, Bertin, E, Brodwin, M, Brooks, D, Buckley-Geer, E, Burke, DL, Carlstrom, JE, Capasso, R, Capozzi, D, Carnero Rosell, A, Kind, MC, Chiu, I, Covarrubias, R, Crawford, TM, Crocce, M, D'Andrea, CB, da Costa, LN, DePoy, DL, Desai, S, de Haan, T, Diehl, HT, Dietrich, JP, Doel, P, Cunha, CE, Eifler, TF, Evrard, AE, Fausti Neto, A, Fernandez, E, Flaugher, B, Fosalba, P, Frieman, J, Gangkofner, C, Gaztanaga, E, Gerdes, D, Gruen, D, Gruendl, RA, Gupta, N, Hennig, C, Holzapfel, WL, Honscheid, K, Jain, B, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Lin, H, Maia, MAG, March, M, Marshall, JL, Martini, P, McDonald, M, Miller, CJ, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Reichardt, CL, Romer, AK, Roodman, A, Sako, M, Sanchez, E, Schubnell, M, Sevilla, I, Smith, RC, Stalder, B, Stark, AA, Strazzullo, V, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Thomas, D, Tucker, D, Vikram, V, von der Linden, A, Walker, AR, Wechsler, RH, Wester, W, Zenteno, A, Ziegler, KE, Saro, A, Bocquet, S, Rozo, E, Benson, BA, Mohr, J, Rykoff, ES, Soares-Santos, M, Bleem, L, Dodelson, S, Melchior, P, Sobreira, F, Upadhyay, V, Weller, J, Abbott, T, Abdalla, FB, Allam, S, Armstrong, R, Banerji, M, Bauer, AH, Bayliss, M, Benoit-Levy, A, Bernstein, GM, Bertin, E, Brodwin, M, Brooks, D, Buckley-Geer, E, Burke, DL, Carlstrom, JE, Capasso, R, Capozzi, D, Carnero Rosell, A, Kind, MC, Chiu, I, Covarrubias, R, Crawford, TM, Crocce, M, D'Andrea, CB, da Costa, LN, DePoy, DL, Desai, S, de Haan, T, Diehl, HT, Dietrich, JP, Doel, P, Cunha, CE, Eifler, TF, Evrard, AE, Fausti Neto, A, Fernandez, E, Flaugher, B, Fosalba, P, Frieman, J, Gangkofner, C, Gaztanaga, E, Gerdes, D, Gruen, D, Gruendl, RA, Gupta, N, Hennig, C, Holzapfel, WL, Honscheid, K, Jain, B, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Lin, H, Maia, MAG, March, M, Marshall, JL, Martini, P, McDonald, M, Miller, CJ, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Reichardt, CL, Romer, AK, Roodman, A, Sako, M, Sanchez, E, Schubnell, M, Sevilla, I, Smith, RC, Stalder, B, Stark, AA, Strazzullo, V, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Thomas, D, Tucker, D, Vikram, V, von der Linden, A, Walker, AR, Wechsler, RH, Wester, W, Zenteno, A, and Ziegler, KE
Published: 2015

21. AUTOMATED TRANSIENT IDENTIFICATION in the DARK ENERGY SURVEY

Author: Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Costa, LND, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Walker, AR, Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Costa, LND, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, and Walker, AR
Abstract: We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (2013 September through 2014 February) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factor of 13.4, while only 1.0% of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility. An implementation of the algorithm and the training data used in this paper are available at http://portal.nserc.gov/project/dessn/autoscan.
Published: 2015

22. AUTOMATED TRANSIENT IDENTIFICATION IN THE DARK ENERGY SURVEY (vol 150, 82, 2015)

Author: Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Levy, A, Bertin, E, Brooks, D, Carnero Rosell, A, Castander, FJ, da Costa, LN, Covarrubias, R, DePoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Fausti Neto, A, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Walker, AR, Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Levy, A, Bertin, E, Brooks, D, Carnero Rosell, A, Castander, FJ, da Costa, LN, Covarrubias, R, DePoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Fausti Neto, A, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, and Walker, AR
Published: 2015

23. Erratum: Automated transient identification in the dark energy survey (AJ (2015) 150 (82))

Author: Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Da Costa, LN, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Walker, AR, Goldstein, DA, Goldstein, DA, D'Andrea, CB, Fischer, JA, Foley, RJ, Gupta, RR, Kessler, R, Kim, AG, Nichol, RC, Nugent, PE, Papadopoulos, A, Sako, M, Smith, M, Sullivan, M, Thomas, RC, Wester, W, Wolf, RC, Abdalla, FB, Banerji, M, Benoit-Lévy, A, Bertin, E, Brooks, D, Rosell, AC, Castander, FJ, Da Costa, LN, Covarrubias, R, Depoy, DL, Desai, S, Diehl, HT, Doel, P, Eifler, TF, Neto, AF, Finley, DA, Flaugher, B, Fosalba, P, Frieman, J, Gerdes, D, Gruen, D, Gruendl, RA, James, D, Kuehn, K, Kuropatkin, N, Lahav, O, Li, TS, Maia, MAG, Makler, M, March, M, Marshall, JL, Martini, P, Merritt, KW, Miquel, R, Nord, B, Ogando, R, Plazas, AA, Romer, AK, Roodman, A, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, and Walker, AR
Published: 2015

24. Search for Gamma-Ray Emission from DES Dwarf Spheroidal Galaxy Candidates with Fermi-LAT Data

Author: Collaboration, The Fermi-LAT, Collaboration, The DES, Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, M., Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, S., Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., Zuntz, J., Collaboration, The Fermi-LAT, Collaboration, The DES, Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, M., Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, S., Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., and Zuntz, J.
Abstract: Due to their proximity, high dark-matter content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of dark matter. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with dark matter halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged dark matter annihilation cross section for these new targets. If the estimated dark-matter content of these dSph candidates is confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for dark matter particles with masses < 20 GeV annihilating via the b-bbar or tau+tau- channels., Comment: 9 pages, 4 figures, 1 table. Updated to published version. Readers may be interested in the related work by Ackermann et al. arXiv:1503.02641 (The Fermi-LAT Collaboration), Bechtol, Drlica-Wagner, et al. arXiv:1503.02584 (The DES Collaboration), and Koposov, Belokurov, Torrealba, & Evans arXiv:1503.02079
Published: 2015
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25. The Difference Imaging Pipeline for the Transient Search in the Dark Energy Survey

Author: Kessler, R., Marriner, J., Childress, M., Covarrubias, R., D'Andrea, C. B., Finley, D. A., Fischer, J., Foley, R. J., Goldstein, D., Gupta, R. R., Kuehn, K., Marcha, M., Nichol, R. C., Papadopoulos, A., Sako, M., Scolnic, D., Smith, M., Sullivan, M., Wester, W., Yuan, F., Abbott, T., Abdalla, F. B., Allam, S., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brooks, D., Rosell, A. Carnero, Kind, M. Carrasco, Castander, F. J., Crocce, M., da Costa, L. N., Desai, S., Diehl, H. T., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., Gruen, D., Gruendl, R. A., Honscheid, K., James, D. J., Kuropatkin, N., Li, T. S., Maia, M. A. G., Marshall, J. L., Martini, P., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., Walker, A. R., Kessler, R., Marriner, J., Childress, M., Covarrubias, R., D'Andrea, C. B., Finley, D. A., Fischer, J., Foley, R. J., Goldstein, D., Gupta, R. R., Kuehn, K., Marcha, M., Nichol, R. C., Papadopoulos, A., Sako, M., Scolnic, D., Smith, M., Sullivan, M., Wester, W., Yuan, F., Abbott, T., Abdalla, F. B., Allam, S., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brooks, D., Rosell, A. Carnero, Kind, M. Carrasco, Castander, F. J., Crocce, M., da Costa, L. N., Desai, S., Diehl, H. T., Eifler, T. F., Neto, A. Fausti, Flaugher, B., Frieman, J., Gruen, D., Gruendl, R. A., Honscheid, K., James, D. J., Kuropatkin, N., Li, T. S., Maia, M. A. G., Marshall, J. L., Martini, P., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., and Walker, A. R.
Abstract: We describe the difference imaging pipeline (DiffImg) used to detect transients in deep images from the Dark Energy Survey Supernova program (DES-SN) in its first observing season from Aug 2013 through Feb 2014. DES-SN is a search for transients in which ten 3-deg^2 fields are repeatedly observed in the g,r,i,z passbands with a cadence of about 1 week. The observing strategy has been optimized to measure high-quality light curves and redshifts for thousands of Type Ia supernova (SN Ia) with the goal of measuring dark energy parameters. The essential DiffImg functions are to align each search image to a deep reference image, do a pixel-by-pixel subtraction, and then examine the subtracted image for significant positive detections of point-source objects. The vast majority of detections are subtraction artifacts, but after selection requirements and image filtering with an automated scanning program, there are 130 detections per deg^2 per observation in each band, of which only 25% are artifacts. Of the 7500 transients discovered by DES-SN in its first observing season, each requiring a detection on at least 2 separate nights, Monte Carlo simulations predict that 27% are expected to be supernova. Another 30% of the transients are artifacts, and most of the remaining transients are AGN and variable stars. Fake SNe Ia are overlaid onto the images to rigorously evaluate detection efficiencies, and to understand the DiffImg performance. The DiffImg efficiency measured with fake SNe agrees well with expectations from a Monte Carlo simulation that uses analytical calculations of the fluxes and their uncertainties. In our 8 "shallow" fields with single-epoch 50% completeness depth 23.5, the SN Ia efficiency falls to 1/2 at redshift z 0.7, in our 2 "deep" fields with mag-depth 24.5, the efficiency falls to 1/2 at z 1.1.
Published: 2015
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26. Constraints on the Richness-Mass Relation and the Optical-SZE Positional Offset Distribution for SZE-Selected Clusters

Author: Saro, A., Bocquet, S., Rozo, E., Benson, B. A., Mohr, J., Rykoff, E. S., Soares-Santos, M., Bleem, L., Dodelson, S., Melchior, P., Sobreira, F., Upadhyay, V., Weller, J., Abbott, T., Abdalla, F. B., Allam, S., Armstrong, R., Banerji, M., Bauer, A. H., Bayliss, M., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brodwin, M., Brooks, D., Buckley-Geer, E., Burke, D. L., Carlstrom, J. E., Capasso, R., Capozzi, D., Rosell, A. Carnero, Kind, M. Carrasco, Chiu, I., Covarrubias, R., Crawford, T. M., Crocce, M., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., de Haan, T., Diehl, H. T., Dietrich, J. P., Doel, P., Cunha, C. E, Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., Gangkofner, C., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gupta, N., Hennig, C., Holzapfel, W. L., Honscheid, K., Jain, B., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Maia, M. A. G., March, M., Marshall, J. L., Martini, Paul, McDonald, M., Miller, C. J., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Reichardt, C. L., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Schubnell, M., Sevilla, I., Smith, R. C., Stalder, B., Stark, A. A., Strazzullo, V., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Vikram, V., von der Linden, A., Walker, A. R., Wechsler, R. H., Wester, W., Zenteno, A., Ziegler, K. E., Saro, A., Bocquet, S., Rozo, E., Benson, B. A., Mohr, J., Rykoff, E. S., Soares-Santos, M., Bleem, L., Dodelson, S., Melchior, P., Sobreira, F., Upadhyay, V., Weller, J., Abbott, T., Abdalla, F. B., Allam, S., Armstrong, R., Banerji, M., Bauer, A. H., Bayliss, M., Benoit-Levy, A., Bernstein, G. M., Bertin, E., Brodwin, M., Brooks, D., Buckley-Geer, E., Burke, D. L., Carlstrom, J. E., Capasso, R., Capozzi, D., Rosell, A. Carnero, Kind, M. Carrasco, Chiu, I., Covarrubias, R., Crawford, T. M., Crocce, M., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., de Haan, T., Diehl, H. T., Dietrich, J. P., Doel, P., Cunha, C. E, Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Flaugher, B., Fosalba, P., Frieman, J., Gangkofner, C., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gupta, N., Hennig, C., Holzapfel, W. L., Honscheid, K., Jain, B., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Maia, M. A. G., March, M., Marshall, J. L., Martini, Paul, McDonald, M., Miller, C. J., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Reichardt, C. L., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Schubnell, M., Sevilla, I., Smith, R. C., Stalder, B., Stark, A. A., Strazzullo, V., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Vikram, V., von der Linden, A., Walker, A. R., Wechsler, R. H., Wester, W., Zenteno, A., and Ziegler, K. E.
Abstract: We cross-match galaxy cluster candidates selected via their Sunyaev-Zel'dovich effect (SZE) signatures in 129.1 deg$^2$ of the South Pole Telescope 2500d SPT-SZ survey with optically identified clusters selected from the Dark Energy Survey (DES) science verification data. We identify 25 clusters between $0.1\lesssim z\lesssim 0.8$ in the union of the SPT-SZ and redMaPPer (RM) samples. RM is an optical cluster finding algorithm that also returns a richness estimate for each cluster. We model the richness $\lambda$-mass relation with the following function $\langle\ln\lambda|M_{500}\rangle\propto B_\lambda\ln M_{500}+C_\lambda\ln E(z)$ and use SPT-SZ cluster masses and RM richnesses $\lambda$ to constrain the parameters. We find $B_\lambda= 1.14^{+0.21}_{-0.18}$ and $C_\lambda=0.73^{+0.77}_{-0.75}$. The associated scatter in mass at fixed richness is $\sigma_{\ln M|\lambda} = 0.18^{+0.08}_{-0.05}$ at a characteristic richness $\lambda=70$. We demonstrate that our model provides an adequate description of the matched sample, showing that the fraction of SPT-SZ selected clusters with RM counterparts is consistent with expectations and that the fraction of RM selected clusters with SPT-SZ counterparts is in mild tension with expectation. We model the optical-SZE cluster positional offset distribution with the sum of two Gaussians, showing that it is consistent with a dominant, centrally peaked population and a sub-dominant population characterized by larger offsets. We also cross-match the RM catalog with SPT-SZ candidates below the official catalog threshold significance $\xi=4.5$, using the RM catalog to provide optical confirmation and redshifts for additional low-$\xi$ SPT-SZ candidates.In this way, we identify 15 additional clusters with $\xi\in [4,4.5]$ over the redshift regime explored by RM in the overlapping region between DES science verification data and the SPT-SZ survey., Comment: 15 pages, 8 Figures, submitted to MNRAS
Published: 2015
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27. DESAlert: Enabling Real-Time Transient Follow-Up with Dark Energy Survey Data

Author: Poci, A., Kuehn, K., Collaboration, the DES, Abbott, T., Abdalla, F. B., Allam, S., Bauer, A. H., Benoit-Lévy, A., Bertin, E., Brooks, D., Brown, P. J., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Covarrubias, R., da Costa, L. N., D'Andrea, C. B., DePoy, D. L., Desai, S., Dietrich, J. P., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., March, M., Marshall, J., Merritt, K. W., Miller, C. J., Nichol, R. C., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla, I., Smith, C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., Walker, A. R., Wester, W., Poci, A., Kuehn, K., Collaboration, the DES, Abbott, T., Abdalla, F. B., Allam, S., Bauer, A. H., Benoit-Lévy, A., Bertin, E., Brooks, D., Brown, P. J., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Covarrubias, R., da Costa, L. N., D'Andrea, C. B., DePoy, D. L., Desai, S., Dietrich, J. P., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., March, M., Marshall, J., Merritt, K. W., Miller, C. J., Nichol, R. C., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla, I., Smith, C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, R. C., Tucker, D., Walker, A. R., and Wester, W.
Abstract: The Dark Energy Survey (DES) is currently undertaking an observational program imaging $1/4$ of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the DES will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts (GRBs) over five years. Once GRBs are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of GRB activity, collates useful information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of GRBs, as well as for identifying key characteristics (e.g., photometric redshifts) of potential GRB host galaxies. We provide the functional details of the DESAlert software as it presently operates, as well as the data products that it produces, and we show sample results from the application of DESAlert to several previously-detected GRBs., Comment: 14 pages, 6 figures, 2 tables. Final version accepted by Publications of the Astronomical Society of Australia
Published: 2015
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28. Automated Transient Identification in the Dark Energy Survey

Author: Goldstein, D. A., D'Andrea, C. B., Fischer, J. A., Foley, R. J., Gupta, R. R., Kessler, R., Kim, A. G., Nichol, R. C., Nugent, P., Papadopoulos, A., Sako, M., Smith, M., Sullivan, M., Thomas, R. C., Wester, W., Wolf, R. C., Abdalla, F. B., Banerji, M., Benoit-Lévy, A., Bertin, E., Brooks, D., Rosell, A. Carnero, Castander, F. J., da Costa, L. N., Covarrubias, R., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., March, M., Marshall, J. L., Martini, P., Merritt, K. W., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Walker, A. R., Goldstein, D. A., D'Andrea, C. B., Fischer, J. A., Foley, R. J., Gupta, R. R., Kessler, R., Kim, A. G., Nichol, R. C., Nugent, P., Papadopoulos, A., Sako, M., Smith, M., Sullivan, M., Thomas, R. C., Wester, W., Wolf, R. C., Abdalla, F. B., Banerji, M., Benoit-Lévy, A., Bertin, E., Brooks, D., Rosell, A. Carnero, Castander, F. J., da Costa, L. N., Covarrubias, R., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Neto, A. Fausti, Finley, D. A., Flaugher, B., Fosalba, P., Frieman, J., Gerdes, D., Gruen, D., Gruendl, R. A., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., March, M., Marshall, J. L., Martini, P., Merritt, K. W., Miquel, R., Nord, B., Ogando, R., Plazas, A. A., Romer, A. K., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., and Walker, A. R.
Abstract: We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (Sep. 2013 through Feb. 2014) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factor of 13.4, while only 1 percent of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility. An implementation of the algorithm and the training data used in this paper are available at http://portal.nersc.gov/project/dessn/autoscan., Comment: 24 pages, 9 figures, 4 tables v3: added link to training data / implementation
Published: 2015
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29. OzDES multi-fibre spectroscopy for the Dark Energy Survey: first-year operation and results

Author: Yuan, Fang, Lidman, C., Davis, T. M., Childress, M., Abdalla, F. B., Banerji, M., Buckley-Geer, E., Rosell, A. Carnero, Carollo, D., Castander, F. J., D'Andrea, C. B., Diehl, H. T., Cunha, C. E, Foley, R. J., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A. G., King, A. L., Kuehn, K., Kuhlmann, S., Lewis, G. F., Lin, H., Martini, P., McMahon, R. G., Mould, J., Nichol, R. C., Norris, R. P., O'Neill, C. R., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A. K., Rooney, P. J., Rozo, E., Rykoff, E. S., Sako, M., Scalzo, R., Schmidt, B. P., Scolnic, D., Seymour, N., Sharp, R., Sobreira, F., Sullivan, M., Thomas, R. C., Tucker, D., Uddin, S. A., Wechsler, R. H., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A. H., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D. L., Kind, M. Carrasco, Covarrubias, R., Crocce, M., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., Marshall, J., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Walker, A. R., Yuan, Fang, Lidman, C., Davis, T. M., Childress, M., Abdalla, F. B., Banerji, M., Buckley-Geer, E., Rosell, A. Carnero, Carollo, D., Castander, F. J., D'Andrea, C. B., Diehl, H. T., Cunha, C. E, Foley, R. J., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A. G., King, A. L., Kuehn, K., Kuhlmann, S., Lewis, G. F., Lin, H., Martini, P., McMahon, R. G., Mould, J., Nichol, R. C., Norris, R. P., O'Neill, C. R., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A. K., Rooney, P. J., Rozo, E., Rykoff, E. S., Sako, M., Scalzo, R., Schmidt, B. P., Scolnic, D., Seymour, N., Sharp, R., Sobreira, F., Sullivan, M., Thomas, R. C., Tucker, D., Uddin, S. A., Wechsler, R. H., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A. H., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D. L., Kind, M. Carrasco, Covarrubias, R., Crocce, M., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Eifler, T. F., Evrard, A. E., Neto, A. Fausti, Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., Marshall, J., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., and Walker, A. R.
Abstract: OzDES is a five-year, 100-night, spectroscopic survey on the Anglo-Australian Telescope, whose primary aim is to measure redshifts of approximately 2,500 Type Ia supernovae host galaxies over the redshift range 0.1 < z < 1.2, and derive reverberation-mapped black hole masses for approximately 500 active galactic nuclei and quasars over 0.3 < z < 4.5. This treasure trove of data forms a major part of the spectroscopic follow-up for the Dark Energy Survey for which we are also targeting cluster galaxies, radio galaxies, strong lenses, and unidentified transients, as well as measuring luminous red galaxies and emission line galaxies to help calibrate photometric redshifts. Here we present an overview of the OzDES program and our first-year results. Between Dec 2012 and Dec 2013, we observed over 10,000 objects and measured more than 6,000 redshifts. Our strategy of retargeting faint objects across many observing runs has allowed us to measure redshifts for galaxies as faint as m_r=25 mag. We outline our target selection and observing strategy, quantify the redshift success rate for different types of targets, and discuss the implications for our main science goals. Finally, we highlight a few interesting objects as examples of the fortuitous yet not totally unexpected discoveries that can come from such a large spectroscopic survey., Comment: 18 pages, 7 figures, submitted to MNRAS
Published: 2015
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30. Search for Gamma-Ray Emission from DES Dwarf Spheroidal Galaxy Candidates with Fermi-LAT Data

Author: Collaboration, The Fermi-LAT, Collaboration, The DES, Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, M., Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, S., Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., Zuntz, J., Collaboration, The Fermi-LAT, Collaboration, The DES, Drlica-Wagner, A., Albert, A., Bechtol, K., Wood, M., Strigari, L., Sanchez-Conde, M., Baldini, L., Essig, R., Cohen-Tanugi, J., Anderson, B., Bellazzini, R., Bloom, E. D., Caputo, R., Cecchi, C., Charles, E., Chiang, J., de Angelis, A., Funk, S., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Guiriec, S., Gustafsson, M., Kuss, M., Loparco, F., Lubrano, P., Mirabal, N., Mizuno, T., Morselli, A., Ohsugi, T., Orlando, E., Persic, M., Raino, S., Sehgal, N., Spada, F., Suson, D. J., Zaharijas, G., Zimmer, S., Abbott, T., Allam, S., Balbinot, E., Bauer, A. H., Benoit-Levy, A., Bernstein, R. A., Bernstein, G. M., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Cunha, C. E, Eifler, T. F., Estrada, J., Evrard, A. E., Neto, A. Fausti, Fernandez, E., Finley, D. A., Flaugher, B., Frieman, J., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Gutierrez, G., Honscheid, K., Jain, B., James, D., Jeltema, T., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Luque, E., Maia, M. A. G., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nord, B., Ogando, R., Peoples, J., Petravick, D., Pieres, A., Plazas, A. A., Queiroz, A., Romer, A. K., Roodman, A., Rykoff, E. S., Sako, M., Sanchez, E., Santiago, B., Scarpine, V., Schubnell, M., Sevilla, I., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Tucker, D., Walker, A., Wechsler, R. H., Wester, W., Williams, P., Yanny, B., and Zuntz, J.
Abstract: Due to their proximity, high dark-matter content, and apparent absence of non-thermal processes, Milky Way dwarf spheroidal satellite galaxies (dSphs) are excellent targets for the indirect detection of dark matter. Recently, eight new dSph candidates were discovered using the first year of data from the Dark Energy Survey (DES). We searched for gamma-ray emission coincident with the positions of these new objects in six years of Fermi Large Area Telescope data. We found no significant excesses of gamma-ray emission. Under the assumption that the DES candidates are dSphs with dark matter halo properties similar to the known dSphs, we computed individual and combined limits on the velocity-averaged dark matter annihilation cross section for these new targets. If the estimated dark-matter content of these dSph candidates is confirmed, they will constrain the annihilation cross section to lie below the thermal relic cross section for dark matter particles with masses < 20 GeV annihilating via the b-bbar or tau+tau- channels., Comment: 9 pages, 4 figures, 1 table. Updated to published version. Readers may be interested in the related work by Ackermann et al. arXiv:1503.02641 (The Fermi-LAT Collaboration), Bechtol, Drlica-Wagner, et al. arXiv:1503.02584 (The DES Collaboration), and Koposov, Belokurov, Torrealba, & Evans arXiv:1503.02079
Published: 2015
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31. Eight New Milky Way Companions Discovered in First-Year Dark Energy Survey Data

Author: The DES Collaboration, Bechtol, K., Drlica-Wagner, A., Balbinot, E., Pieres, A., Simon, J. D., Yanny, B., Santiago, B., Wechsler, R. H., Frieman, J., Walker, A. R., Williams, P., Rozo, E., Rykoff, E. S., Queiroz, A., Luque, E., Benoit-Levy, A., Tucker, D., Sevilla, I., Gruendl, R. A., da Costa, L. N., Neto, A. Fausti, Maia, M. A. G., Abbott, T., Allam, S., Armstrong, R., Bauer, A. H., Bernstein, G. M., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T. F., Estrada, J., Evrard, A. E., Fernandez, E., Finley, D. A., Flaugher, B., Gaztanaga, E., Gerdes, D., Girardi, L., Gladders, M., Gruen, D., Gutierrez, G., Hao, J., Honscheid, K., Jain, B., James, D., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nichol, R., Nord, B., Ogando, R., Peoples, J., Petravick, D., Plazas, A. A., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Wester, W., Zuntz, J., The DES Collaboration, Bechtol, K., Drlica-Wagner, A., Balbinot, E., Pieres, A., Simon, J. D., Yanny, B., Santiago, B., Wechsler, R. H., Frieman, J., Walker, A. R., Williams, P., Rozo, E., Rykoff, E. S., Queiroz, A., Luque, E., Benoit-Levy, A., Tucker, D., Sevilla, I., Gruendl, R. A., da Costa, L. N., Neto, A. Fausti, Maia, M. A. G., Abbott, T., Allam, S., Armstrong, R., Bauer, A. H., Bernstein, G. M., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Castander, F. J., Covarrubias, R., D'Andrea, C. B., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T. F., Estrada, J., Evrard, A. E., Fernandez, E., Finley, D. A., Flaugher, B., Gaztanaga, E., Gerdes, D., Girardi, L., Gladders, M., Gruen, D., Gutierrez, G., Hao, J., Honscheid, K., Jain, B., James, D., Kent, S., Kron, R., Kuehn, K., Kuropatkin, N., Lahav, O., Li, T. S., Lin, H., Makler, M., March, M., Marshall, J., Martini, P., Merritt, K. W., Miller, C., Miquel, R., Mohr, J., Neilsen, E., Nichol, R., Nord, B., Ogando, R., Peoples, J., Petravick, D., Plazas, A. A., Romer, A. K., Roodman, A., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Smith, R. C., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Thomas, D., Wester, W., and Zuntz, J.
Abstract: We report the discovery of eight new Milky Way companions in ~1,800 deg^2 of optical imaging data collected during the first year of the Dark Energy Survey (DES). Each system is identified as a statistically significant over-density of individual stars consistent with the expected isochrone and luminosity function of an old and metal-poor stellar population. The objects span a wide range of absolute magnitudes (M_V from -2.2 mag to -7.4 mag), physical sizes (10 pc to 170 pc), and heliocentric distances (30 kpc to 330 kpc). Based on the low surface brightnesses, large physical sizes, and/or large Galactocentric distances of these objects, several are likely to be new ultra-faint satellite galaxies of the Milky Way and/or Magellanic Clouds. We introduce a likelihood-based algorithm to search for and characterize stellar over-densities, as well as identify stars with high satellite membership probabilities. We also present completeness estimates for detecting ultra-faint galaxies of varying luminosities, sizes, and heliocentric distances in the first-year DES data., Comment: 33 pages, 12 figures, 3 tables. Accepted for publication in ApJ. Readers may be interested in the concurrent work by Koposov, Belokurov, Torrealba, & Evans (http://arxiv.org/abs/1503.02079). Indirect dark matter search results are presented in Drlica-Wagner, Albert, Bechtol, Wood, Strigari, et al. (The LAT and DES Collaborations, http://arxiv.org/abs/1503.02632)
Published: 2015
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32. DES13S2cmm: The First Superluminous Supernova from the Dark Energy Survey

Author: Papadopoulos, A., D'Andrea, C. B., Sullivan, M., Nichol, R. C., Barbary, K., Biswas, R., Brown, P. J., Covarrubias, R. A., Finley, D. A., Fischer, J. A., Foley, R. J., Goldstein, D., Gupta, R. R., Kessler, R., Kovacs, E., Kuhlmann, S. E., Lidman, C., March, M., Nugent, P. E., Sako, M., Smith, R. C., Spinka, H., Wester, W., Abbott, T. M. C., Abdalla, F., Allam, S. S., Banerji, M., Bernstein, J. P., Bernstein, R. A., Carnero, A., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T., Evrard, A. E., Flaugher, B., Frieman, J. A., Gerdes, D., Gruen, D., Honscheid, K., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Maia, M. A. G., Makler, M., Marshall, J. L., Merritt, K. W., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roe, N. A., Romer, A. K., Rykoff, E., Sanchez, E., Santiago, B. X., Scarpine, V., Schubnell, M., Sevilla, I., Santos, M. Soares, Suchyta, E., Swanson, M., Tarle, G., Thaler, J., Tucker, D. L., Wechsler, R. H., Zuntz, J., Papadopoulos, A., D'Andrea, C. B., Sullivan, M., Nichol, R. C., Barbary, K., Biswas, R., Brown, P. J., Covarrubias, R. A., Finley, D. A., Fischer, J. A., Foley, R. J., Goldstein, D., Gupta, R. R., Kessler, R., Kovacs, E., Kuhlmann, S. E., Lidman, C., March, M., Nugent, P. E., Sako, M., Smith, R. C., Spinka, H., Wester, W., Abbott, T. M. C., Abdalla, F., Allam, S. S., Banerji, M., Bernstein, J. P., Bernstein, R. A., Carnero, A., da Costa, L. N., DePoy, D. L., Desai, S., Diehl, H. T., Eifler, T., Evrard, A. E., Flaugher, B., Frieman, J. A., Gerdes, D., Gruen, D., Honscheid, K., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., Maia, M. A. G., Makler, M., Marshall, J. L., Merritt, K. W., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roe, N. A., Romer, A. K., Rykoff, E., Sanchez, E., Santiago, B. X., Scarpine, V., Schubnell, M., Sevilla, I., Santos, M. Soares, Suchyta, E., Swanson, M., Tarle, G., Thaler, J., Tucker, D. L., Wechsler, R. H., and Zuntz, J.
Abstract: We present DES13S2cmm, the first spectroscopically-confirmed superluminous supernova (SLSN) from the Dark Energy Survey (DES). We briefly discuss the data and search algorithm used to find this event in the first year of DES operations, and outline the spectroscopic data obtained from the European Southern Observatory (ESO) Very Large Telescope to confirm its redshift (z = 0.663 +/- 0.001 based on the host-galaxy emission lines) and likely spectral type (type I). Using this redshift, we find M_U_peak = -21.05 +0.10 -0.09 for the peak, rest-frame U-band absolute magnitude, and find DES13S2cmm to be located in a faint, low metallicity (sub-solar), low stellar-mass host galaxy (log(M/M_sun) = 9.3 +/- 0.3); consistent with what is seen for other SLSNe-I. We compare the bolometric light curve of DES13S2cmm to fourteen similarly well-observed SLSNe-I in the literature and find it possesses one of the slowest declining tails (beyond +30 days rest frame past peak), and is the faintest at peak. Moreover, we find the bolometric light curves of all SLSNe-I studied herein possess a dispersion of only 0.2-0.3 magnitudes between +25 and +30 days after peak (rest frame) depending on redshift range studied; this could be important for 'standardising' such supernovae, as is done with the more common type Ia. We fit the bolometric light curve of DES13S2cmm with two competing models for SLSNe-I - the radioactive decay of 56Ni, and a magnetar - and find that while the magnetar is formally a better fit, neither model provides a compelling match to the data. Although we are unable to conclusively differentiate between these two physical models for this particular SLSN-I, further DES observations of more SLSNe-I should break this degeneracy, especially if the light curves of SLSNe-I can be observed beyond 100 days in the rest frame of the supernova., Comment: Accepted by MNRAS (2015 January 23), 13 pages, 6 figures, 2 tables
Published: 2015
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33. OzDES multifibre spectroscopy for the Dark Energy Survey: first-year operation and results

Author: Yuan, Fang, Lidman, C., Davis, T. M., Childress, M., Abdalla, F. B., Banerji, M., Buckley-Geer, E., Carnero Rosell, A., Carollo, D., Castander, F. J., D'Andrea, C. B., Diehl, H. T., Cunha, C. E., Foley, R. J., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A. G., King, A. L., Kuehn, K., Kuhlmann, S., Lewis, G. F., Lin, H., Martini, P., McMahon, R. G., Mould, J., Nichol, R. C., Norris, R. P., O'Neill, C. R., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A. K., Rooney, P. J., Rozo, E., Rykoff, E. S., Sako, M., Scalzo, R., Schmidt, B. P., Scolnic, D., Seymour, N., Sharp, R., Sobreira, F., Sullivan, M., Thomas, R. C., Tucker, D., Uddin, S. A., Wechsler, R. H., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A. H., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D. L., Kind, M. Carrasco, Covarrubias, R., Crocce, M., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Eifler, T. F., Evrard, A. E., Fausti Neto, A., Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., Marshall, J., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., Walker, A. R., Yuan, Fang, Lidman, C., Davis, T. M., Childress, M., Abdalla, F. B., Banerji, M., Buckley-Geer, E., Carnero Rosell, A., Carollo, D., Castander, F. J., D'Andrea, C. B., Diehl, H. T., Cunha, C. E., Foley, R. J., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A. G., King, A. L., Kuehn, K., Kuhlmann, S., Lewis, G. F., Lin, H., Martini, P., McMahon, R. G., Mould, J., Nichol, R. C., Norris, R. P., O'Neill, C. R., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A. K., Rooney, P. J., Rozo, E., Rykoff, E. S., Sako, M., Scalzo, R., Schmidt, B. P., Scolnic, D., Seymour, N., Sharp, R., Sobreira, F., Sullivan, M., Thomas, R. C., Tucker, D., Uddin, S. A., Wechsler, R. H., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A. H., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D. L., Kind, M. Carrasco, Covarrubias, R., Crocce, M., da Costa, L. N., DePoy, D. L., Desai, S., Doel, P., Eifler, T. F., Evrard, A. E., Fausti Neto, A., Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R. A., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T. S., Maia, M. A. G., Makler, M., Marshall, J., Miller, C. J., Miquel, R., Ogando, R., Plazas, A. A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thaler, J., and Walker, A. R.
Published: 2015

34. OzDES multifibre spectroscopy for the Dark Energy Survey: first-year operation and results

Author: Yuan, F., Lidman, C., Davis, T., Childress, M., Abdalla, F., Banerji, M., Buckley-Geer, E., Carnero Rosell, A., Carollo, D., Castander, F., D'Andrea, C., Diehl, H., Cunha, C., Foley, R., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A., King, A., Kuehn, K., Kuhlmann, S., Lewis, G., Lin, H., Martini, P., McMahon, R., Mould, J., Nichol, R., Norris, R., O'Neill, C., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A., Rooney, P., Rozo, E., Rykoff, E., Sako, M., Scalzo, R., Schmidt, B., Scolnic, D., Seymour, Nick, Sharp, R., Sobreira, F., Sullivan, M., Thomas, R., Tucker, D., Uddin, S., Wechsler, R., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D., Kind, M., Covarrubias, R., Crocce, M., da Costa, L., DePoy, D., Desai, S., Doel, P., Eifler, T., Evrard, A., Fausti Neto, A., Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T., Maia, M., Makler, M., Marshall, J., Miller, C., Miquel, R., Ogando, R., Plazas, A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R., Soares-Santos, M., Suchyta, E., Swanson, M., Tarle, G., Thaler, J., Walker, A., Yuan, F., Lidman, C., Davis, T., Childress, M., Abdalla, F., Banerji, M., Buckley-Geer, E., Carnero Rosell, A., Carollo, D., Castander, F., D'Andrea, C., Diehl, H., Cunha, C., Foley, R., Frieman, J., Glazebrook, K., Gschwend, J., Hinton, S., Jouvel, S., Kessler, R., Kim, A., King, A., Kuehn, K., Kuhlmann, S., Lewis, G., Lin, H., Martini, P., McMahon, R., Mould, J., Nichol, R., Norris, R., O'Neill, C., Ostrovski, F., Papadopoulos, A., Parkinson, D., Reed, S., Romer, A., Rooney, P., Rozo, E., Rykoff, E., Sako, M., Scalzo, R., Schmidt, B., Scolnic, D., Seymour, Nick, Sharp, R., Sobreira, F., Sullivan, M., Thomas, R., Tucker, D., Uddin, S., Wechsler, R., Wester, W., Wilcox, H., Zhang, B., Abbott, T., Allam, S., Bauer, A., Benoit-Levy, A., Bertin, E., Brooks, D., Burke, D., Kind, M., Covarrubias, R., Crocce, M., da Costa, L., DePoy, D., Desai, S., Doel, P., Eifler, T., Evrard, A., Fausti Neto, A., Flaugher, B., Fosalba, P., Gaztanaga, E., Gerdes, D., Gruen, D., Gruendl, R., Honscheid, K., James, D., Kuropatkin, N., Lahav, O., Li, T., Maia, M., Makler, M., Marshall, J., Miller, C., Miquel, R., Ogando, R., Plazas, A., Roodman, A., Sanchez, E., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R., Soares-Santos, M., Suchyta, E., Swanson, M., Tarle, G., Thaler, J., and Walker, A.
Published: 2015

35. Observational constraints on the progenitor metallicities of core-collapse supernovae

Author: Anderson, J. P., Covarrubias, R. A., James, P. A., Hamuy, M., Habergham, S. M., Anderson, J. P., Covarrubias, R. A., James, P. A., Hamuy, M., and Habergham, S. M.
Abstract: We present constraints on the progenitor metallicities of core-collapse supernovae. To date, nearly all metallicity constraints have been inferred from indirect methods such as metallicity gradients in host galaxies, luminosities of host galaxies, or derived global galaxy metallicities. Here, progenitor metallicities are derived from optical spectra taken at the sites of nearby supernovae, from the ratio of strong emission lines found in their host HII regions.We present results from the spectra of 74 host HII regions and discuss the implications that these have on the nature of core-collapse supernova progenitors. Overall, while we find that the mean metallicity of type Ibc environments is higher than that of type II events, this difference is smaller than observed in previous studies. There is only a 0.06 dex difference in the mean metallicity values, at a statistical significance of ~1.5 sigma, while using a KS-test we find that the two metallicity distributions are marginally consistent with being drawn from the same parent population (probability >10%). This argues that progenitor metallicity is not a dominant parameter in deciding supernovae type, with progenitor mass and/or binarity playing a much more significant role., Comment: ACCEPTED for publication in MNRAS
Published: 2010
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36. Observational constraints on the progenitor metallicities of core-collapse supernovae

Author: Anderson, J. P., Covarrubias, R. A., James, P. A., Hamuy, M., Habergham, S. M., Anderson, J. P., Covarrubias, R. A., James, P. A., Hamuy, M., and Habergham, S. M.
Abstract: We present constraints on the progenitor metallicities of core-collapse supernovae. To date, nearly all metallicity constraints have been inferred from indirect methods such as metallicity gradients in host galaxies, luminosities of host galaxies, or derived global galaxy metallicities. Here, progenitor metallicities are derived from optical spectra taken at the sites of nearby supernovae, from the ratio of strong emission lines found in their host HII regions.We present results from the spectra of 74 host HII regions and discuss the implications that these have on the nature of core-collapse supernova progenitors. Overall, while we find that the mean metallicity of type Ibc environments is higher than that of type II events, this difference is smaller than observed in previous studies. There is only a 0.06 dex difference in the mean metallicity values, at a statistical significance of ~1.5 sigma, while using a KS-test we find that the two metallicity distributions are marginally consistent with being drawn from the same parent population (probability >10%). This argues that progenitor metallicity is not a dominant parameter in deciding supernovae type, with progenitor mass and/or binarity playing a much more significant role., Comment: ACCEPTED for publication in MNRAS
Published: 2010
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37. Exploring the Outer Solar System with the ESSENCE Supernova Survey

Author: Becker, A. C., Arraki, K., Kaib, N. A., Wood-Vasey, W. M., Aguilera, C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Riess, A. G., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Suntzeff, N. B., Tonry, J. L., Zenteno, A., Becker, A. C., Arraki, K., Kaib, N. A., Wood-Vasey, W. M., Aguilera, C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Riess, A. G., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Suntzeff, N. B., Tonry, J. L., and Zenteno, A.
Abstract: We report the discovery and orbit determination of 14 trans-Neptunian objects (TNOs) from the ESSENCE Supernova Survey difference imaging dataset. Two additional objects discovered in a similar search of the SDSS-II Supernova Survey database were recovered in this effort. ESSENCE repeatedly observed fields far from the Solar System ecliptic (-21 deg < beta < -5 deg), reaching limiting magnitudes per observation of I~23.1 and R~23.7. We examine several of the newly detected objects in detail, including 2003 UC_414 which orbits entirely between Uranus and Neptune and lies very close to a dynamical region that would make it stable for the lifetime of the Solar System. 2003 SS_422 and 2007 TA_418 have high eccentricities and large perihelia, making them candidate members of an outer class of trans-Neptunian objects. We also report a new member of the ''extended'' or ''detached'' scattered disk, 2004 VN_112, and verify the stability of its orbit using numerical simulations. This object would have been visible to ESSENCE for only ~2% of its orbit, suggesting a vast number of similar objects across the sky. We emphasize that off-ecliptic surveys are optimal for uncovering the diversity of such objects, which in turn will constrain the history of gravitational influences that shaped our early Solar System., Comment: 5 pages, 1 table, accepted for publication in ApJL
Published: 2008
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38. Improved Cosmological Constraints from New, Old and Combined Supernova Datasets

Author: Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., Balland, C., Barbary, K., Blanc, G., Challis, P. J., Conley, A., Connolly, N. V., Covarrubias, R., Dawson, K. S., Deustua, S. E., Ellis, R., Fabbro, S., Fadeyev, V., Fan, X., Farris, B., Folatelli, G., Frye, B. L., Garavini, G., Gates, E. L., Germany, L., Goldhaber, G., Goldman, B., Goobar, A., Groom, D. E., Haissinski, J., Hardin, D., Hook, I., Kent, S., Kim, A. G., Knop, R. A., Lidman, C., Linder, E. V., Mendez, J., Meyers, J., Miller, G. J., Moniez, M., Mourao, A. M., Newberg, H., Nobili, S., Nugent, P. E., Pain, R., Perdereau, O., Perlmutter, S., Phillips, M. M., Prasad, V., Quimby, R., Regnault, N., Rich, J., Rubenstein, E. P., Ruiz-Lapuente, P., Santos, F. D., Schaefer, B. E., Schommer, R. A., Smith, R. C., Soderberg, A. M., Spadafora, A. L., Strolger, L. -G., Strovink, M., Suntzeff, N. B., Suzuki, N., Thomas, R. C., Walton, N. A., Wang, L., Wood-Vasey, W. M., Yun, J. L., Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., Balland, C., Barbary, K., Blanc, G., Challis, P. J., Conley, A., Connolly, N. V., Covarrubias, R., Dawson, K. S., Deustua, S. E., Ellis, R., Fabbro, S., Fadeyev, V., Fan, X., Farris, B., Folatelli, G., Frye, B. L., Garavini, G., Gates, E. L., Germany, L., Goldhaber, G., Goldman, B., Goobar, A., Groom, D. E., Haissinski, J., Hardin, D., Hook, I., Kent, S., Kim, A. G., Knop, R. A., Lidman, C., Linder, E. V., Mendez, J., Meyers, J., Miller, G. J., Moniez, M., Mourao, A. M., Newberg, H., Nobili, S., Nugent, P. E., Pain, R., Perdereau, O., Perlmutter, S., Phillips, M. M., Prasad, V., Quimby, R., Regnault, N., Rich, J., Rubenstein, E. P., Ruiz-Lapuente, P., Santos, F. D., Schaefer, B. E., Schommer, R. A., Smith, R. C., Soderberg, A. M., Spadafora, A. L., Strolger, L. -G., Strovink, M., Suntzeff, N. B., Suzuki, N., Thomas, R. C., Walton, N. A., Wang, L., Wood-Vasey, W. M., and Yun, J. L.
Abstract: We present a new compilation of Type Ia supernovae (SNe Ia), a new dataset of low-redshift nearby-Hubble-flow SNe and new analysis procedures to work with these heterogeneous compilations. This ``Union'' compilation of 414 SN Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older datasets, as well as the recently extended dataset of distant supernovae observed with HST. A single, consistent and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers. We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO). The constraint we obtain from supernovae on the dark energy density is $\Omega_\Lambda= 0.713^{+0.027}_{-0.029} (stat)}^{+0.036}_{-0.039} (sys)}$, for a flat, LCDM Universe. Assuming a constant equation of state parameter, $w$, the combined constraints from SNe, BAO and CMB give $w=-0.969^{+0.059}_{-0.063}(stat)^{+0.063}_{-0.066} (sys)$. While our results are consistent with a cosmological constant, we obtain only relatively weak constraints on a $w$ that varies with redshift. In particular, the current SN data do not yet significantly constrain $w$ at $z>1$. With the addition of our new nearby Hubble-flow SNe Ia, these resulting cosmological constraints are currently the tightest available., Comment: 49 pages, 17 figures; accepted for publication in Astrophysical Journal. For data tables, code for cosmological analysis and full-resolution figures, see http://supernova.lbl.gov/Union
Published: 2008
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39. Spectral Identification of an Ancient Supernova using Light Echoes in the LMC

Author: Rest, A., Matheson, T., Blondin, S., Bergmann, M., Welch, D. L., Suntzeff, N. B., Smith, R. C., Olsen, K., Prieto, J. L., Garg, A., Challis, P., Stubbs, C., Hicken, M., Modjaz, M., Wood-Vasey, W. M., Zenteno, A., Damke, G., Newman, A., Huber, M., Cook, K. H., Nikolaev, S., Becker, A. C., Miceli, A., Covarrubias, R., Morelli, L., Pignata, G., Clocchiatti, A., Minniti, D., Foley, R. J., Rest, A., Matheson, T., Blondin, S., Bergmann, M., Welch, D. L., Suntzeff, N. B., Smith, R. C., Olsen, K., Prieto, J. L., Garg, A., Challis, P., Stubbs, C., Hicken, M., Modjaz, M., Wood-Vasey, W. M., Zenteno, A., Damke, G., Newman, A., Huber, M., Cook, K. H., Nikolaev, S., Becker, A. C., Miceli, A., Covarrubias, R., Morelli, L., Pignata, G., Clocchiatti, A., Minniti, D., and Foley, R. J.
Abstract: We report the successful identification of the type of the supernova responsible for the supernova remnant SNR 0509-675 in the Large Magellanic Cloud (LMC) using Gemini spectra of surrounding light echoes. The ability to classify outbursts associated with centuries-old remnants provides a new window into several aspects of supernova research and is likely to be successful in providing new constraints on additional LMC supernovae as well as their historical counterparts in the Milky Way Galaxy (MWG). The combined spectrum of echo light from SNR 0509-675 shows broad emission and absorption lines consistent with a supernova (SN) spectrum. We create a spectral library consisting of 26 SNe Ia and 6 SN Ib/c that are time-integrated, dust-scattered by LMC dust, and reddened by the LMC and MWG. We fit these SN templates to the observed light echo spectrum using $\chi^2$ minimization as well as correlation techniques, and we find that overluminous 91T-like SNe Ia with $\dm15<0.9$ match the observed spectrum best., Comment: 12 pages, 18 Figures, to be published in ApJ
Published: 2008
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40. Spectral Identification of an Ancient Supernova using Light Echoes in the LMC

Author: Rest, A., Matheson, T., Blondin, S., Bergmann, M., Welch, D. L., Suntzeff, N. B., Smith, R. C., Olsen, K., Prieto, J. L., Garg, A., Challis, P., Stubbs, C., Hicken, M., Modjaz, M., Wood-Vasey, W. M., Zenteno, A., Damke, G., Newman, A., Huber, M., Cook, K. H., Nikolaev, S., Becker, A. C., Miceli, A., Covarrubias, R., Morelli, L., Pignata, G., Clocchiatti, A., Minniti, D., Foley, R. J., Rest, A., Matheson, T., Blondin, S., Bergmann, M., Welch, D. L., Suntzeff, N. B., Smith, R. C., Olsen, K., Prieto, J. L., Garg, A., Challis, P., Stubbs, C., Hicken, M., Modjaz, M., Wood-Vasey, W. M., Zenteno, A., Damke, G., Newman, A., Huber, M., Cook, K. H., Nikolaev, S., Becker, A. C., Miceli, A., Covarrubias, R., Morelli, L., Pignata, G., Clocchiatti, A., Minniti, D., and Foley, R. J.
Abstract: We report the successful identification of the type of the supernova responsible for the supernova remnant SNR 0509-675 in the Large Magellanic Cloud (LMC) using Gemini spectra of surrounding light echoes. The ability to classify outbursts associated with centuries-old remnants provides a new window into several aspects of supernova research and is likely to be successful in providing new constraints on additional LMC supernovae as well as their historical counterparts in the Milky Way Galaxy (MWG). The combined spectrum of echo light from SNR 0509-675 shows broad emission and absorption lines consistent with a supernova (SN) spectrum. We create a spectral library consisting of 26 SNe Ia and 6 SN Ib/c that are time-integrated, dust-scattered by LMC dust, and reddened by the LMC and MWG. We fit these SN templates to the observed light echo spectrum using $\chi^2$ minimization as well as correlation techniques, and we find that overluminous 91T-like SNe Ia with $\dm15<0.9$ match the observed spectrum best., Comment: 12 pages, 18 Figures, to be published in ApJ
Published: 2008
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41. Spectral Identification of an Ancient Supernova using Light Echoes in the LMC

Author: Rest, A., Matheson, T., Blondin, S., Bergmann, M., Welch, D. L., Suntzeff, N. B., Smith, R. C., Olsen, K., Prieto, J. L., Garg, A., Challis, P., Stubbs, C., Hicken, M., Modjaz, M., Wood-Vasey, W. M., Zenteno, A., Damke, G., Newman, A., Huber, M., Cook, K. H., Nikolaev, S., Becker, A. C., Miceli, A., Covarrubias, R., Morelli, L., Pignata, G., Clocchiatti, A., Minniti, D., Foley, R. J., Rest, A., Matheson, T., Blondin, S., Bergmann, M., Welch, D. L., Suntzeff, N. B., Smith, R. C., Olsen, K., Prieto, J. L., Garg, A., Challis, P., Stubbs, C., Hicken, M., Modjaz, M., Wood-Vasey, W. M., Zenteno, A., Damke, G., Newman, A., Huber, M., Cook, K. H., Nikolaev, S., Becker, A. C., Miceli, A., Covarrubias, R., Morelli, L., Pignata, G., Clocchiatti, A., Minniti, D., and Foley, R. J.
Abstract: We report the successful identification of the type of the supernova responsible for the supernova remnant SNR 0509-675 in the Large Magellanic Cloud (LMC) using Gemini spectra of surrounding light echoes. The ability to classify outbursts associated with centuries-old remnants provides a new window into several aspects of supernova research and is likely to be successful in providing new constraints on additional LMC supernovae as well as their historical counterparts in the Milky Way Galaxy (MWG). The combined spectrum of echo light from SNR 0509-675 shows broad emission and absorption lines consistent with a supernova (SN) spectrum. We create a spectral library consisting of 26 SNe Ia and 6 SN Ib/c that are time-integrated, dust-scattered by LMC dust, and reddened by the LMC and MWG. We fit these SN templates to the observed light echo spectrum using $\chi^2$ minimization as well as correlation techniques, and we find that overluminous 91T-like SNe Ia with $\dm15<0.9$ match the observed spectrum best., Comment: 12 pages, 18 Figures, to be published in ApJ
Published: 2008
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42. Exploring the Outer Solar System with the ESSENCE Supernova Survey

Author: Becker, A. C., Arraki, K., Kaib, N. A., Wood-Vasey, W. M., Aguilera, C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Riess, A. G., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Suntzeff, N. B., Tonry, J. L., Zenteno, A., Becker, A. C., Arraki, K., Kaib, N. A., Wood-Vasey, W. M., Aguilera, C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Damke, G., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Riess, A. G., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Suntzeff, N. B., Tonry, J. L., and Zenteno, A.
Abstract: We report the discovery and orbit determination of 14 trans-Neptunian objects (TNOs) from the ESSENCE Supernova Survey difference imaging dataset. Two additional objects discovered in a similar search of the SDSS-II Supernova Survey database were recovered in this effort. ESSENCE repeatedly observed fields far from the Solar System ecliptic (-21 deg < beta < -5 deg), reaching limiting magnitudes per observation of I~23.1 and R~23.7. We examine several of the newly detected objects in detail, including 2003 UC_414 which orbits entirely between Uranus and Neptune and lies very close to a dynamical region that would make it stable for the lifetime of the Solar System. 2003 SS_422 and 2007 TA_418 have high eccentricities and large perihelia, making them candidate members of an outer class of trans-Neptunian objects. We also report a new member of the ''extended'' or ''detached'' scattered disk, 2004 VN_112, and verify the stability of its orbit using numerical simulations. This object would have been visible to ESSENCE for only ~2% of its orbit, suggesting a vast number of similar objects across the sky. We emphasize that off-ecliptic surveys are optimal for uncovering the diversity of such objects, which in turn will constrain the history of gravitational influences that shaped our early Solar System., Comment: 5 pages, 1 table, accepted for publication in ApJL
Published: 2008
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43. Improved Cosmological Constraints from New, Old and Combined Supernova Datasets

Author: Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., Balland, C., Barbary, K., Blanc, G., Challis, P. J., Conley, A., Connolly, N. V., Covarrubias, R., Dawson, K. S., Deustua, S. E., Ellis, R., Fabbro, S., Fadeyev, V., Fan, X., Farris, B., Folatelli, G., Frye, B. L., Garavini, G., Gates, E. L., Germany, L., Goldhaber, G., Goldman, B., Goobar, A., Groom, D. E., Haissinski, J., Hardin, D., Hook, I., Kent, S., Kim, A. G., Knop, R. A., Lidman, C., Linder, E. V., Mendez, J., Meyers, J., Miller, G. J., Moniez, M., Mourao, A. M., Newberg, H., Nobili, S., Nugent, P. E., Pain, R., Perdereau, O., Perlmutter, S., Phillips, M. M., Prasad, V., Quimby, R., Regnault, N., Rich, J., Rubenstein, E. P., Ruiz-Lapuente, P., Santos, F. D., Schaefer, B. E., Schommer, R. A., Smith, R. C., Soderberg, A. M., Spadafora, A. L., Strolger, L. -G., Strovink, M., Suntzeff, N. B., Suzuki, N., Thomas, R. C., Walton, N. A., Wang, L., Wood-Vasey, W. M., Yun, J. L., Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., Balland, C., Barbary, K., Blanc, G., Challis, P. J., Conley, A., Connolly, N. V., Covarrubias, R., Dawson, K. S., Deustua, S. E., Ellis, R., Fabbro, S., Fadeyev, V., Fan, X., Farris, B., Folatelli, G., Frye, B. L., Garavini, G., Gates, E. L., Germany, L., Goldhaber, G., Goldman, B., Goobar, A., Groom, D. E., Haissinski, J., Hardin, D., Hook, I., Kent, S., Kim, A. G., Knop, R. A., Lidman, C., Linder, E. V., Mendez, J., Meyers, J., Miller, G. J., Moniez, M., Mourao, A. M., Newberg, H., Nobili, S., Nugent, P. E., Pain, R., Perdereau, O., Perlmutter, S., Phillips, M. M., Prasad, V., Quimby, R., Regnault, N., Rich, J., Rubenstein, E. P., Ruiz-Lapuente, P., Santos, F. D., Schaefer, B. E., Schommer, R. A., Smith, R. C., Soderberg, A. M., Spadafora, A. L., Strolger, L. -G., Strovink, M., Suntzeff, N. B., Suzuki, N., Thomas, R. C., Walton, N. A., Wang, L., Wood-Vasey, W. M., and Yun, J. L.
Abstract: We present a new compilation of Type Ia supernovae (SNe Ia), a new dataset of low-redshift nearby-Hubble-flow SNe and new analysis procedures to work with these heterogeneous compilations. This ``Union'' compilation of 414 SN Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older datasets, as well as the recently extended dataset of distant supernovae observed with HST. A single, consistent and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers. We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO). The constraint we obtain from supernovae on the dark energy density is $\Omega_\Lambda= 0.713^{+0.027}_{-0.029} (stat)}^{+0.036}_{-0.039} (sys)}$, for a flat, LCDM Universe. Assuming a constant equation of state parameter, $w$, the combined constraints from SNe, BAO and CMB give $w=-0.969^{+0.059}_{-0.063}(stat)^{+0.063}_{-0.066} (sys)$. While our results are consistent with a cosmological constant, we obtain only relatively weak constraints on a $w$ that varies with redshift. In particular, the current SN data do not yet significantly constrain $w$ at $z>1$. With the addition of our new nearby Hubble-flow SNe Ia, these resulting cosmological constraints are currently the tightest available., Comment: 49 pages, 17 figures; accepted for publication in Astrophysical Journal. For data tables, code for cosmological analysis and full-resolution figures, see http://supernova.lbl.gov/Union
Published: 2008
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44. Improved Cosmological Constraints from New, Old, and Combined Supernova Data Sets

Author: Fundação para a Ciência e a Tecnologia (Portugal), German Research Foundation, Department of Energy (US), Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., Balland, C., Barbary, K., Blanc, G., Challis, P. J., Conley, A., Connolly, N. V., Covarrubias, R., Dawson, K.S., Deustua, S. E., Ellis, R., Fabbro, S., Fadeyev, V., Fan, X., Farris, B., Folatelli, G., Frye, B.L., Garavini, G., Gates, E. L., Germany, L., Goldhaber, G., Goldman, B., Goobar, A., Groom, D. E., Haissinski, J., Hardin, D., Hook, I., Kent, S., Kim, A. G., Knop, R. A., Lidman, C., Linder, E.V., Méndez, J., Meyers, J., Miller, G. J., Moniez, M., Mourão, A. M., Newberg, H., Nobili, S., Nugent, P. E., Pain, R., Perdereau, O., Perlmutter, S., Phillips, M. M., Prasad, V., Quimby, R., Regnault, N., Rich, J., Rubenstein, E. P., Ruiz-Lapuente, Pilar, Santos, F. D., Schaefer, B. E., Schommer, R. A., Smith, R. C., Soderberg, A. M., Spadafora, A. L., Strolger, L. G., Strovink, M., Suntzeff, Nicholas B., Suzuki, N., Thomas, R. C., Walton, N. A., Wang, L., Wood-Vasey, W. M., Yun, J. L., Fundação para a Ciência e a Tecnologia (Portugal), German Research Foundation, Department of Energy (US), Kowalski, M., Rubin, D., Aldering, G., Agostinho, R. J., Amadon, A., Amanullah, R., Balland, C., Barbary, K., Blanc, G., Challis, P. J., Conley, A., Connolly, N. V., Covarrubias, R., Dawson, K.S., Deustua, S. E., Ellis, R., Fabbro, S., Fadeyev, V., Fan, X., Farris, B., Folatelli, G., Frye, B.L., Garavini, G., Gates, E. L., Germany, L., Goldhaber, G., Goldman, B., Goobar, A., Groom, D. E., Haissinski, J., Hardin, D., Hook, I., Kent, S., Kim, A. G., Knop, R. A., Lidman, C., Linder, E.V., Méndez, J., Meyers, J., Miller, G. J., Moniez, M., Mourão, A. M., Newberg, H., Nobili, S., Nugent, P. E., Pain, R., Perdereau, O., Perlmutter, S., Phillips, M. M., Prasad, V., Quimby, R., Regnault, N., Rich, J., Rubenstein, E. P., Ruiz-Lapuente, Pilar, Santos, F. D., Schaefer, B. E., Schommer, R. A., Smith, R. C., Soderberg, A. M., Spadafora, A. L., Strolger, L. G., Strovink, M., Suntzeff, Nicholas B., Suzuki, N., Thomas, R. C., Walton, N. A., Wang, L., Wood-Vasey, W. M., and Yun, J. L.
Abstract: We present a new compilation of Type Ia supernovae (SNe Ia), a new data set of low-redshift nearby-Hubble-flow SNe, and new analysis procedures to work with these heterogeneous compilations. This >Union> compilation of 414 SNe Ia, which reduces to 307 SNe after selection cuts, includes the recent large samples of SNe Ia from the Supernova Legacy Survey and ESSENCE Survey, the older data sets, as well as the recently extended data set of distant supernovae observed with the Hubble Space Telescope (HST). A single, consistent, and blind analysis procedure is used for all the various SN Ia subsamples, and a new procedure is implemented that consistently weights the heterogeneous data sets and rejects outliers. We present the latest results from this Union compilation and discuss the cosmological constraints from this new compilation and its combination with other cosmological measurements (CMB and BAO). The constraint we obtain from supernovae on the dark energy density is ¿¿ = 0.713+ 0.027¿0.029(stat)+ 0.036¿0.039(sys) , for a flat, ¿CDM universe. Assuming a constant equation of state parameter, w, the combined constraints from SNe, BAO, and CMB give w = ¿ 0.969+ 0.059¿0.063(stat)+ 0.063¿0.066(sys) . While our results are consistent with a cosmological constant, we obtain only relatively weak constraints on a w that varies with redshift. In particular, the current SN data do not yet significantly constrain w at z > 1. With the addition of our new nearby Hubble-flow SNe Ia, these resulting cosmological constraints are currently the tightest available.
Published: 2008

45. The ESSENCE supernova survey : Survey optimization, observations, and supernova photometry

Author: Miknaitis, G., Pignata, G., Rest, A., Wood-Vasey, W. M., Blondin, S., Challis, P., Smith, R. C., Stubbs, C. W., Suntzeff, N. B., Foley, R. J., Matheson, T., Tonry, J. L., Aguilera, C., Blackman, J. W., Becker, A. C., Clocchiatti, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Krisciunas, K., Kirshner, R. P., Leibundgut, B., Li, W., Miceli, A., Narayan, G., Prieto, J. L., Riess, A. G., Salvo, M. E., Schmidt, B. P., Sollerman, Jesper, Spyromilio, J., Zenteno, A., Miknaitis, G., Pignata, G., Rest, A., Wood-Vasey, W. M., Blondin, S., Challis, P., Smith, R. C., Stubbs, C. W., Suntzeff, N. B., Foley, R. J., Matheson, T., Tonry, J. L., Aguilera, C., Blackman, J. W., Becker, A. C., Clocchiatti, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Krisciunas, K., Kirshner, R. P., Leibundgut, B., Li, W., Miceli, A., Narayan, G., Prieto, J. L., Riess, A. G., Salvo, M. E., Schmidt, B. P., Sollerman, Jesper, Spyromilio, J., and Zenteno, A.
Abstract: We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the dark energy equation-of-state parameter, w = P/(rho c(2)). We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to w for a given fixed amount of telescope time. For our survey on the CTIO 4 m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z approximate to 0: 5 +/- 0: 2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in nearly real time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their apparent brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4 m telescope's natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 Type Ia supernovae, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for all of the Type Ia supernovae found by ESSENCE and used in our measurement of w, presented in a companion paper by Wood-Vasey and coworkers., authorCount :36
Published: 2007
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46. Observational constraints on the nature of dark energy : First cosmological results from the ESSENCE supernova survey

Author: Wood-Vasey, W. M., Miknaitis, G., Stubbs, C. W., Jha, S., Riess, A. G., Garnavich, P. M., Kirshner, R. P., Aguilera, C., Becker, A. C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Conley, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Hicken, M., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, Jesper, Spyromilio, J., Tonry, J. L., Suntzeff, N. B., Zenteno, A., Wood-Vasey, W. M., Miknaitis, G., Stubbs, C. W., Jha, S., Riess, A. G., Garnavich, P. M., Kirshner, R. P., Aguilera, C., Becker, A. C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Conley, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Hicken, M., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, Jesper, Spyromilio, J., Tonry, J. L., Suntzeff, N. B., and Zenteno, A.
Abstract: We present constraints on the dark energy equation-of-state parameter, w = P/(rho c(2)), using 60 SNe Ia fromthe ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat universe. By including constraints on (Omega(M), w) from baryon acoustic oscillations, we obtain a value for a static equation-of-state parameter w = -1:05(-0.12)(+0: 13) (stat 1 sigma) +/- 0: 13 (sys) and Omega(M) = 0:274(-0.020)(+0:033) (stat 1 sigma) with a bestfit chi(2)/dof of 0.96. These results are consistent with those reported by the Supernova Legacy Survey from the first year of a similar program measuring supernova distances and redshifts. We evaluate sources of systematic error that afflict supernova observations and present Monte Carlo simulations that explore these effects. Currently, the largest systematic with the potential to affect our measurements is the treatment of extinction due to dust in the supernova host galaxies. Combining our set of ESSENCE SNe Ia with the first-results Supernova Legacy Survey SNe Ia, we obtain a joint constraint of w = -1:07(-0: 09)(+0:09) (stat 1 sigma) +/- 0: 13 ( sys), Omega(M) 0:267(-0:028)(+0:028) (stat 1 sigma) with a best-fit chi(2)/dof of 0.91. The current global SN Ia data alone rule out empty (Omega(M) = 0), matter-only Omega(M) = 0: 3, and Omega(M) = 1 universes at > 4.5 sigma. The current SN Ia data are fully consistent with a cosmological constant., authorCount :37
Published: 2007
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47. The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry

Author: Miknaitis, G., Pignata, G., Rest, A., Wood-Vasey, W. M., Blondin, S., Challis, P., Smith, R. C., Stubbs, C. W., Suntzeff, N. B., Foley, R. J., Matheson, T., Tonry, J. L., Aguilera, C., Blackman, J. W., Becker, A. C., Clocchiatti, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Krisciunas, K., Kirshner, R. P., Leibundgut, B., Li, W., Miceli, A., Narayan, G., Prieto, J. L., Riess, A. G., Salvo, M. E., Schmidt, B. P., Sollerman, J., Spyromilio, J., Zenteno, A., Miknaitis, G., Pignata, G., Rest, A., Wood-Vasey, W. M., Blondin, S., Challis, P., Smith, R. C., Stubbs, C. W., Suntzeff, N. B., Foley, R. J., Matheson, T., Tonry, J. L., Aguilera, C., Blackman, J. W., Becker, A. C., Clocchiatti, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Garg, A., Garnavich, P. M., Hicken, M., Jha, S., Krisciunas, K., Kirshner, R. P., Leibundgut, B., Li, W., Miceli, A., Narayan, G., Prieto, J. L., Riess, A. G., Salvo, M. E., Schmidt, B. P., Sollerman, J., Spyromilio, J., and Zenteno, A.
Abstract: We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the equation of state parameter of the dark energy. We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to the dark energy equation of state parameter w=P/rho c^2 for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z~0.5 +- 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in near real-time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4m natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 type Ia SNe, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for the all type Ia supernovae found by ESSENCE and used in our measurement of w, presented in Wood-Vasey et al, 2007., Comment: Submitted to ApJ. Companion paper to Wood-Vasey et al (2007). Electronic tables available at http://www.ctio.noao.edu/essence/wresults
Published: 2007
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48. Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey

Author: Wood-Vasey, W. M., Miknaitis, G., Stubbs, C. W., Jha, S., Riess, A. G., Garnavich, P. M., Kirshner, R. P., Aguilera, C., Becker, A. C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Conley, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Hicken, M., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Tonry, J. L., Suntzeff, N. B., Zenteno, A., Wood-Vasey, W. M., Miknaitis, G., Stubbs, C. W., Jha, S., Riess, A. G., Garnavich, P. M., Kirshner, R. P., Aguilera, C., Becker, A. C., Blackman, J. W., Blondin, S., Challis, P., Clocchiatti, A., Conley, A., Covarrubias, R., Davis, T. M., Filippenko, A. V., Foley, R. J., Garg, A., Hicken, M., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Narayan, G., Pignata, G., Prieto, J. L., Rest, A., Salvo, M. E., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Tonry, J. L., Suntzeff, N. B., and Zenteno, A.
Abstract: We present constraints on the dark energy equation-of-state parameter, w=P/(rho c^2), using 60 Type Ia supernovae (SNe Ia) from the ESSENCE supernova survey. We derive a set of constraints on the nature of the dark energy assuming a flat Universe. By including constraints on (Omega_M, w) from baryon acoustic oscillations, we obtain a value for a static equation-of-state parameter w=-1.05^{+0.13}_{-0.12} (stat; 1 sigma) +- 0.11 (sys) and Omega_M=0.274^{+0.033}_{-0.020} (stat; 1 sigma) with a best-fit chi^2/DoF of 0.96. These results are consistent with those reported by the SuperNova Legacy Survey in a similar program measuring supernova distances and redshifts. We evaluate sources of systematic error that afflict supernova observations and present Monte Carlo simulations that explore these effects. Currently, the largest systematic currently with the potential to affect our measurements is the treatment of extinction due to dust in the supernova host galaxies. Combining our set of ESSENCE SNe Ia with the SuperNova Legacy Survey SNe Ia, we obtain a joint constraint of w=-1.07^{+0.09}_{-0.09} (stat; 1 sigma) +- 0.12 (sys), Omega_M=0.267^{+0.028}_{-0.018} (stat; 1 sigma) with a best-fit chi^2/DoF of 0.91. The current SN Ia data are fully consistent with a cosmological constant., Comment: Submitted to ApJ. 82 pages. 9 figures. 10 tables. Companion paper to Miknaitis et al (2007). Electronic tables and probability surfaces available at http://www.ctio.noao.edu/essence/wresults
Published: 2007
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49. Constraining Cosmic Evolution of Type Ia Supernovae

Author: Foley, Ryan J., Filippenko, A. V., Aguilera, C., Becker, A. C., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Davis, T. M., Garnavich, P. M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Pignata, G., Rest, A., Riess, A. G., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Tonry, J. L., Suntzeff, N. B., Wood-Vasey, W. M., Zenteno, A., Foley, Ryan J., Filippenko, A. V., Aguilera, C., Becker, A. C., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Davis, T. M., Garnavich, P. M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Pignata, G., Rest, A., Riess, A. G., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Tonry, J. L., Suntzeff, N. B., Wood-Vasey, W. M., and Zenteno, A.
Abstract: We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 UV spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with the same slit width, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be ~0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of ~3% in the optical and growing toward the UV. The difference between the maximum light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical., Comment: 22 pages, 22 figures, submitted to ApJ. Composite spectra can be downloaded from http://astro.berkeley.edu/~rfoley/composite
Published: 2007
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50. Constraining Cosmic Evolution of Type Ia Supernovae

Author: Foley, Ryan J., Filippenko, A. V., Aguilera, C., Becker, A. C., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Davis, T. M., Garnavich, P. M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Pignata, G., Rest, A., Riess, A. G., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Tonry, J. L., Suntzeff, N. B., Wood-Vasey, W. M., Zenteno, A., Foley, Ryan J., Filippenko, A. V., Aguilera, C., Becker, A. C., Blondin, S., Challis, P., Clocchiatti, A., Covarrubias, R., Davis, T. M., Garnavich, P. M., Jha, S., Kirshner, R. P., Krisciunas, K., Leibundgut, B., Li, W., Matheson, T., Miceli, A., Miknaitis, G., Pignata, G., Rest, A., Riess, A. G., Schmidt, B. P., Smith, R. C., Sollerman, J., Spyromilio, J., Stubbs, C. W., Tonry, J. L., Suntzeff, N. B., Wood-Vasey, W. M., and Zenteno, A.
Abstract: We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 UV spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with the same slit width, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be ~0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of ~3% in the optical and growing toward the UV. The difference between the maximum light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical., Comment: 22 pages, 22 figures, submitted to ApJ. Composite spectra can be downloaded from http://astro.berkeley.edu/~rfoley/composite
Published: 2007
Full Text: View/download PDF

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