85 results on '"W. S. Burgett"'
Search Results
2. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova
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S. Geier, F. Fürst, E. Ziegerer, T. Kupfer, U. Heber, A. Irrgang, B. Wang, Z. Liu, Z. Han, B. Sesar, D. Levitan, R. Kotak, E. Magnier, K. Smith, W. S. Burgett, K. Chambers, H. Flewelling, N. Kaiser, R. Wainscoat, and C. Waters
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- 2015
- Full Text
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3. Charge Diffusion Variations in Pan-STARRS1 CCDs
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Eugene A. Magnier, J. L. Tonry, D. Finkbeiner, E. Schlafly, W. S. Burgett, K. C. Chambers, H. A. Flewelling, K. W. Hodapp, N. Kaiser, R.-P. Kudritzki, N. Metcalfe, R. J. Wainscoat, and C. Z. Waters
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- 2018
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4. A Pan-STARRS 1 study of the relationship between wide binarity and planet occurrence in theKeplerfield
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Richard J. Wainscoat, K. C. Chambers, Niall R. Deacon, Klaus-Werner Hodapp, Andrew W. Mann, Nick Kaiser, Adam L. Kraus, Christopher Waters, Eugene A. Magnier, John L. Tonry, H. Flewelling, and W. S. Burgett
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FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Kepler-47 ,Planet ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Kepler-62 ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,010308 nuclear & particles physics ,Kepler-22b ,Exomoon ,Astronomy ,Astronomy and Astrophysics ,Planetary system ,Exoplanet ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,Kepler-62c - Abstract
The NASA Kepler mission has revolutionised time-domain astronomy and has massively expanded the number of known extrasolar planets. However, the effect of wide multiplicity on exoplanet occurrence has not been tested with this dataset. We present a sample of 401 wide multiple systems containing at least one Kepler target star. Our method uses Pan-STARRS1 and archival data to produce an accurate proper motion catalogue of the Kepler field. Combined with Pan-STARRS1 SED fits and archival proper motions for bright stars, we use a newly developed probabilistic algorithm to identify likely wide binary pairs which are not chance associations. As by-products of this we present stellar SED templates in the Pan-STARRS1 photometric system and conversions from this system to Kepler magnitudes. We find that Kepler target stars in our binary sample with separations above 6 arcseconds are no more or less likely to be identified as confirmed or candidate planet hosts than a weighted comparison sample of Kepler targets of similar brightness and spectral type. Therefore we find no evidence that binaries with projected separations greater than 3,000AU affect the occurrence rate of planets with P, 15 figures, 6 tables, MNRAS accepted, Tables 1 and 4 available from http://www.star.herts.ac.uk/~ndeacon/PS1Kepler.html . Replacement updates Figure 11 and the text referring to it
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- 2015
5. The Complete Light-curve Sample of Spectroscopically Confirmed SNe Ia from Pan-STARRS1 and Cosmological Constraints from the Combined Pantheon Sample
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K. W. Smith, D. P. Finkbeiner, J. Hand, S. J. Smartt, S. Rodney, John L. Tonry, Elizabeth N. Johnson, M. McCrum, E. E. E. Gall, E. A. Magnier, Christopher W. Stubbs, R. P. Kudritzki, W. S. Burgett, David O. Jones, Peter W. Draper, Nathan Edward Sanders, W. M. Wood-Vasey, F. Bresolin, R. Lunnan, Daniel Scolnic, M. E. Huber, Yen-Chen Pan, Gautham Narayan, Peter Challis, Ryan J. Foley, K. C. Chambers, Nick Kaiser, Klaus W. Hodapp, Richard Kessler, D. J. Brout, R. Chornock, Maria R. Drout, Armin Rest, R. P. Kirshner, Michael Foley, Edo Berger, Edward F. Schlafly, Adam G. Riess, Rubina Kotak, and Nigel Metcalfe
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Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Cosmic microwave background ,FOS: Physical sciences ,Cosmological constant ,Astrophysics ,Astronomy & Astrophysics ,Physical Chemistry ,01 natural sciences ,Atomic ,Photometry (optics) ,symbols.namesake ,Particle and Plasma Physics ,supernovae: general ,0103 physical sciences ,Nuclear ,Planck ,dark energy ,010303 astronomy & astrophysics ,Physics ,010308 nuclear & particles physics ,Molecular ,Astronomy and Astrophysics ,Light curve ,Redshift ,observations [cosmology] ,cosmology: observations ,Supernova ,Space and Planetary Science ,Dark energy ,symbols ,astro-ph.CO ,general [supernovae] ,Astronomical and Space Sciences ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Physical Chemistry (incl. Structural) - Abstract
We present optical light curves, redshifts, and classifications for 365 spectroscopically confirmed Type Ia supernovae (SNe Ia) discovered by the Pan-STARRS1 (PS1) Medium Deep Survey. We detail improvements to the PS1 SN photometry, astrometry and calibration that reduce the systematic uncertainties in the PS1 SN Ia distances. We combine the subset of 279 PS1 SN Ia ($0.03 < z < 0.68$) with useful distance estimates of SN Ia from SDSS, SNLS, various low-z and HST samples to form the largest combined sample of SN Ia consisting of a total of 1048 SN Ia ranging from $0.01 < z < 2.3$, which we call the `Pantheon Sample'. When combining Planck 2015 CMB measurements with the Pantheon SN sample, we find $��_m=0.307\pm0.012$ and $w = -1.026\pm0.041$ for the wCDM model. When the SN and CMB constraints are combined with constraints from BAO and local H0 measurements, the analysis yields the most precise measurement of dark energy to date: $w0 = -1.007\pm 0.089$ and $wa = -0.222 \pm0.407$ for the w0waCDM model. Tension with a cosmological constant previously seen in an analysis of PS1 and low-z SNe has diminished after an increase of $2\times$ in the statistics of the PS1 sample, improved calibration and photometry, and stricter light-curve quality cuts. We find the systematic uncertainties in our measurements of dark energy are almost as large as the statistical uncertainties, primarily due to limitations of modeling the low-redshift sample. This must be addressed for future progress in using SN Ia to measure dark energy., Accepted by ApJ. Data can be found here: http://dx.DOI.org/10.17909/T95Q4X
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- 2018
6. Physical properties of 15 quasars at z ≳ 6.5
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Bram Venemans, R. P. Kudritzki, W. S. Burgett, Anna-Christina Eilers, D. Stern, Joseph F. Hennawi, X. Fan, C. L. Waters, Chiara Mazzucchelli, Jochen Greiner, E. A. Magnier, H. W. Rix, Nigel Metcalfe, Fabian Walter, R. J. Wainscoat, Eduardo Bañados, E. Farina, Edward F. Schlafly, Roberto Decarli, K. C. Chambers, Nick Kaiser, Robert A. Simcoe, Peter W. Draper, and G. De Rosa
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Physics ,Supermassive black hole ,education.field_of_study ,010308 nuclear & particles physics ,media_common.quotation_subject ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Galaxy ,Universe ,Redshift ,Black hole ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Continuum (set theory) ,education ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,media_common - Abstract
Quasars are galaxies hosting accreting supermassive black holes; due to their brightness, they are unique probes of the early universe. To date, only few quasars have been reported at $z > 6.5$ ($
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- 2017
7. 2MASS 0213+3648 C : a wide T3 benchmark companion to an an active, old M dwarf binary
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E. A. Magnier, W. S. Burgett, Peter W. Draper, Niall R. Deacon, H. Flewelling, R. J. Wainscoat, W. E. Sweeney, K. C. Chambers, Nick Kaiser, Klaus W. Hodapp, William M. J. Best, Brendan P. Bowler, C. L. Waters, Michael C. Liu, Nigel Metcalfe, Joshua Schlieder, and Kimberly M. Aller
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Physics ,Brightness ,010308 nuclear & particles physics ,Brown dwarf ,Binary number ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,10. No inequality ,010303 astronomy & astrophysics ,Na absorption ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
We present the discovery of a 360 AU separation T3 companion to the tight (3.1 AU) M4.5+M6.5 binary 2MASS J02132062+3648506. This companion was identified using Pan-STARRS1 data and, despite its relative proximity to the Sun (22.2$_{-4.0}^{+6.4}$ pc; Pan-STARRS1 parallax) and brightness ($J$=15.3), appears to have been missed by previous studies due to its position near a diffraction spike in 2MASS. The close M~dwarf binary has active X-ray and H$\alpha$ emission and shows evidence for UV flares. The binary's weak {\it GALEX} UV emission and strong Na I 8200\AA Na absorption leads us to an age range of $\sim$1-10Gyr. Applying this age range to evolutionary models implies the wide companion has a mass of 0.063$\pm$0.009\,$M_{\odot}$. 2MASS J0213+3648 C provides a relatively old benchmark close to the L/T transition and acts as a key, older comparison to the much younger early-T companions HN~Peg~B and GU~Psc~b., Comment: 14 pages, 12 figures, 2 tables, accepted for publication in MNRAS Updated in 2 column format
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- 2017
8. Hiding in plain sight – recovering clusters of galaxies with the strongest AGN in their cores
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T. S. Green, Alastair C. Edge, Rolf-Peter Kudritzki, Eugene A. Magnier, Nick Kaiser, W. S. Burgett, Richard J. Wainscoat, Peter W. Draper, Harald Ebeling, Nigel Metcalfe, and Christopher Waters
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Physics ,Active galactic nucleus ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,Luminosity ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,ROSAT ,Cluster (physics) ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
A key challenge in understanding the feedback mechanism of AGN in Brightest Cluster Galaxies (BCGs) is the inherent rarity of catching an AGN during its strong outburst phase. This is exacerbated by the ambiguity of differentiating between AGN and clusters in X-ray observations. If there is evidence for an AGN then the X-ray emission is commonly assumed to be dominated by the AGN emission, introducing a selection effect against the detection of AGN in BCGs. In order to recover these 'missing' clusters, we systematically investigate the colour-magnitude relation around some ~3500 ROSAT All Sky Survey selected AGN, looking for signs of a cluster red sequence. Amongst our 22 candidate systems, we independently rediscover several confirmed systems, where a strong AGN resides in a central galaxy. We compare the X-ray luminosity to red sequence richness distribution of our AGN candidate systems with that of a similarly selected comparison sample of ~1000 confirmed clusters and identify seven 'best' candidates (all of which are BL Lac objects), where the X-ray flux is likely to be a comparable mix between cluster and AGN emission. We confirm that the colours of the red sequence are consistent with the redshift of the AGN, that the colours of the AGN host galaxy are consistent with AGN, and, by comparing their luminosities with those from our comparison clusters, confirm that the AGN hosts are consistent with BCGs., Accepted for publication in MNRAS; 12 Pages + Appendix; 7 Figures and 4 Tables
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- 2017
9. The discovery of eight z ~ 6 quasars from Pan-STARRS1
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Emanuele Paolo Farina, Xiaohui Fan, Ian D. McGreer, Christopher Waters, Bram Venemans, Eugene A. Magnier, H. W. Rix, John Morgan, Rolf-Peter Kudritzki, Christopher W. Stubbs, Paul A. Price, Fabian Walter, Nigel Metcalfe, Eduardo Bañados, Nick Kaiser, John L. Tonry, Robert A. Simcoe, G. De Rosa, Axel Weiß, Richard J. Wainscoat, K. C. Chambers, W. E. Sweeney, Jochen Greiner, Eric Morganson, Linhua Jiang, Roberto Decarli, and W. S. Burgett
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Physics ,Supermassive black hole ,education.field_of_study ,Population ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Redshift ,law.invention ,Telescope ,Space and Planetary Science ,law ,Intergalactic medium ,Emission spectrum ,education ,Reionization - Abstract
High-redshift quasars are unique probes of the evolution of supermassive black holes and the intergalactic medium at the end of the epoch of reionization. We present the optical spectra of eight new z ~ 6 quasars selected from the Panoramic Survey Telescope & Rapid Response System 1 (Pan-STARRS1). Details of the selection strategy can be found in Bañados et al. (2014). With this work we increase the number of known quasars at z < 5.7 by more than 10%. The quasars discovered here span a large range of luminosities (19.6 ≤ zP1 ≤ 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show weak or no Lyα emission line. We find a larger fraction of weak–line emission quasars than in lower redshift studies, although still based on low number statistics, this may imply that the quasar population could be more diverse than previously thought.
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- 2013
10. Composite reverberation mapping
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Brandon C. Kelly, Tom Shanks, Paul J. Green, W. S. Burgett, Paul A. Price, Eugene A. Magnier, S. Fine, Edo Berger, Scott M. Croom, and Ryan Chornock
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Seyfert. [Galaxies] ,QSOS ,Physics ,Reverberation ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,active [Galaxies] ,FOS: Physical sciences ,general [Quasars] ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Large Synoptic Survey Telescope ,Light curve ,Redshift ,Computational physics ,Correlation function (statistical mechanics) ,emission lines [Quasars] ,Amplitude ,Space and Planetary Science ,nuclei [Galaxies] ,Reverberation mapping ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Reverberation mapping offers one of the best techniques for studying the inner regions of QSOs. It is based on cross-correlating continuum and emission-line light curves. New time-resolved optical surveys will produce well sampled light curves for many thousands of QSOs. We explore the potential of stacking samples to produce composite cross-correlations for groups of objects that have well sampled continuum light curves, but only a few (~2) emission-line measurements. This technique exploits current and future wide-field optical monitoring surveys (e.g. Pan-STARRS, LSST) and the multiplexing capability of multi-object spectrographs (e.g. 2dF, Hectospec) to significantly reduce the observational expense of reverberation mapping, in particular at high redshift (0.5 to 2.5). We demonstrate the technique using simulated QSO light curves and explore the biases involved when stacking cross-correlations in some simplified situations. We show that stacked cross correlations have smaller amplitude peaks compared to well sampled correlation functions as the mean flux of the emission light curve is poorly constrained. However, the position of the peak remains intact. We find there can be `kinks' in stacked correlation functions due to different measurements contributing to different parts of the correlation function. Using the Pan-STARRS Medium-Deep Survey (MDS) as a template we show that cross-correlation lags should be measurable in a sample size of 500 QSOs that have weekly photometric monitoring and two spectroscopic observations. Finally we apply the technique to a small sample (42) of QSOs that have light curves from the MDS. We find no indication of a peak in the stacked cross-correlation. A larger spectroscopic sample is required to produce robust reverberation lags., 11 pages, 11 figures, accepted for publication in MNRAS
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- 2012
11. Dust in three dimensions in the Galactic Plane
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Richard J. Wainscoat, R. J. Hanson, John L. Tonry, Klaus-Werner Hodapp, K. C. Chambers, W. S. Burgett, Coryn A. L. Bailer-Jones, Christopher Waters, and Nick Kaiser
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Physics ,Number density ,010308 nuclear & particles physics ,Extinction (astronomy) ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galactic plane ,Effective temperature ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Distance modulus ,Stars ,Photometry (astronomy) ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Angular resolution (graph drawing) ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We present three dimensional maps in monochromatic extinction $A_{\rm 0}$ and the extinction parameter $R_0$ within a few degrees of the Galactic plane. These are inferred using photometry from the Pan-STARRS1 and Spitzer Glimpse surveys of nearly $20$ million stars located in the region $l = 0-250^{\circ}$ and from $b = -4.5^{\circ}$ to $b=4.5^{\circ}$. Given the available stellar number density, we use an angular resolution of $7' \times 7'$ and steps of $1{\rm mag}$ in distance modulus. We simultaneously estimate distance modulus and effective temperature $T_{\rm eff}$ alongside the other parameters for stars individually using the method of \citet{Hanson2014} before combining these estimates to a complete map. The full maps are available via the MNRAS website., Accepted for publication in MNRAS. Free-access version available at http://mnras.oxfordjournals.org/cgi/content/abstract/stw2240?ijkey=8TdulFJR3q3ppl1&keytype=ref - data temporarily available at http://www.rhanson.de/gpdust
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- 2016
12. M Dwarf Activity in the Pan-STARRS 1 Medium-Deep Survey: First Catalog and Rotation Periods
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Rolf-Peter Kudritzki, M. E. Huber, Andrew W. Mann, Nick Kaiser, Armin Rest, Erin Kado-Fong, Richard J. Wainscoat, W. S. Burgett, K. C. Chambers, Edo Berger, Christopher Waters, Eugene A. Magnier, and Peter K. G. Williams
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Physics ,010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Rotation ,01 natural sciences ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences - Abstract
We report on an ongoing project to investigate activity in the M dwarf stellar population observed by the Pan-STARRS 1 Medium Deep Survey (PS1-MDS). Using a custom-built pipeline, we refine an initial sample of $\approx$ 4 million sources in PS1-MDS to a sample of 184,148 candidate cool stars using color cuts. Motivated by the well-known relationship between rotation and stellar activity, we use a multi-band periodogram analysis and visual vetting to identify 271 sources that are likely rotating M dwarfs. We derive a new set of polynomials relating M dwarf PS1 colors to fundamental stellar parameters and use them to estimate the masses, distances, effective temperatures, and bolometric luminosities of our sample. We present a catalog containing these values, our measured rotation periods, and cross-matches to other surveys. Our final sample spans periods of $\lesssim$1-130 days in stars with estimated effective temperatures of $\approx$ 2700-4000 K. Twenty-two of our sources have X-ray cross-matches, and they are found to be relatively X-ray bright as would be expected from selection effects. Our data set provides evidence that Kepler-based searches have not been sensitive to very slowly-rotating stars ($P_{\rm rot} \gtrsim 70$ d), implying that the observed emergence of very slow rotators in studies of low-mass stars may be a systematic effect. We also see a lack of low-amplitude ($, Comment: 20 pages, 11 figures. Submitted to ApJ
- Published
- 2016
13. A Multi-Wavelength Photometric Census of AGN and Star Formation Activity in the Brightest Cluster Galaxies of X-ray Selected Clusters
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Alastair C. Edge, Peter W. Draper, T. S. Green, John P. Stott, Christopher Waters, Harald Ebeling, Nigel Metcalfe, Richard J. Wainscoat, K. C. Chambers, Nick Kaiser, and W. S. Burgett
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Physics ,education.field_of_study ,Active galactic nucleus ,010308 nuclear & particles physics ,Star formation ,media_common.quotation_subject ,Population ,Astronomy ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Galaxy ,Space and Planetary Science ,Sky ,Intracluster medium ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,ROSAT ,Cluster (physics) ,education ,010303 astronomy & astrophysics ,media_common - Abstract
Despite their reputation as being "red and dead", the unique environment inhabited by Brightest Cluster Galaxies (BCGs) can often lead to a self-regulated feedback cycle between radiatively cooling intracluster gas and star formation and AGN activity in the BCG. However the prevalence of "active" BCGs, and details of the feedback involved, are still uncertain. We have performed an optical, UV and Mid-IR photometric analysis of the BCGs in 981 clusters at 0.03 < z < 0.5, selected from the ROSAT All Sky Survey. Using Pan-STARRS PS1 3pi, GALEX and WISE survey data we look for BCGs with photometric colours which deviate from that of the bulk population of passive BCGs - indicative of AGN and/or star formation activity within the BCG. We find that whilst the majority of BCGs are consistent with being passive, at least 14% of our BCGs show a significant colour offset from passivity in at least one colour index. And, where available, supplementary spectroscopy reveals the majority of these particular BCGs show strong optical emission lines. On comparing BCG "activity" with the X-ray luminosity of the host cluster, we find that BCGs showing a colour offset are preferentially found in the more X-ray luminous clusters, indicative of the connection between BCG "activity" and the intracluster medium., Accepted for Publication in MNRAS; 17 Pages + Appendix, 18 Figures and 5 Tables
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- 2016
- Full Text
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14. SUPERNOVA 2009kf: AN ULTRAVIOLET BRIGHT TYPE IIP SUPERNOVA DISCOVERED WITH PAN-STARRS 1 AND GALEX
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John L. Tonry, H. Flewelling, Carrie Trundle, Seppo Mattila, K. W. Smith, S. J. Smartt, C. G. Wynn-Williams, Peter M. Onaka, Christopher W. Stubbs, T. Grav, Christopher M. Waters, John Morgan, E. A. Magnier, David G. Monet, S. Valenti, A. Pastorello, Mark Waterson, R. J. Wainscoat, D. R. Young, D. C. Martin, G. A. Luppino, M. E. Huber, M. T. Botticella, Walter A. Siegmund, P. A. Price, W. M. Wood-Vasey, Rubina Kotak, Armin Rest, W. E. Sweeney, Adam G. Riess, Gautham Narayan, Erkki Kankare, Nick Kaiser, Klaus W. Hodapp, R. P. Kudritzki, W. S. Burgett, P. H. Rhoads, F. Bresolin, S. Rodney, J. N. Heasley, K. Forster, Suvi Gezari, K. C. Chambers, Robert H. Lupton, James D. Neill, and T. Dombeck
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Absolute magnitude ,Physics ,Supernova ,Space and Planetary Science ,Astronomy and Astrophysics ,Radius ,Astrophysics ,Effective temperature ,Ejecta ,Light curve ,Luminosity - Abstract
We present photometric and spectroscopic observations of a luminous Type IIP Supernova (SN) 2009kf discovered by the Pan-STARRS 1 (PS1) survey and also detected by the Galaxy Evolution Explorer. The SN shows a plateau in its optical and bolometric light curves, lasting approximately 70 days in the rest frame, with an absolute magnitude of M_V = -18.4 mag. The P-Cygni profiles of hydrogen indicate expansion velocities of 9000 km s^(-1) at 61 days after discovery which is extremely high for a Type IIP SN. SN 2009kf is also remarkably bright in the near-ultraviolet (NUV) and shows a slow evolution 10-20 days after optical discovery. The NUV and optical luminosity at these epochs can be modeled with a blackbody with a hot effective temperature (T ~ 16,000 K) and a large radius (R ~ 1 × 10^(15) cm). The bright bolometric and NUV luminosity, the light curve peak and plateau duration, the high velocities, and temperatures suggest that 2009kf is a Type IIP SN powered by a larger than normal explosion energy. Recently discovered high-z SNe (0.7 < z < 2.3) have been assumed to be IIn SNe, with the bright UV luminosities due to the interaction of SN ejecta with a dense circumstellar medium. UV-bright SNe similar to SN 2009kf could also account for these high-z events, and its absolute magnitude M_(NUV) = -21.5 ± 0.5 mag suggests such SNe could be discovered out to z ~ 2.5 in the PS1 survey.
- Published
- 2010
15. SEARCHING FOR SUB-KILOMETER TRANS-NEPTUNIAN OBJECTS USING PAN-STARRS VIDEO MODE LIGHT CURVES: PRELIMINARY STUDY AND EVALUATION USING ENGINEERING DATA
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J.-H. Wang, P. Protopapas, W.-P. Chen, C. R. Alcock, W. S. Burgett, T. Dombeck, T. Grav, J. S. Morgan, P. A. Price, and J. L. Tonry
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Physics ,Stars ,010504 meteorology & atmospheric sciences ,Space and Planetary Science ,0103 physical sciences ,Mode (statistics) ,Astronomy and Astrophysics ,Field of view ,Astrophysics ,Guide star ,010303 astronomy & astrophysics ,01 natural sciences ,0105 earth and related environmental sciences - Abstract
We present a pre-survey study of using Pan-STARRS high sampling rate video mode guide star images to search for TNOs. With suitable selection of the guide stars within the Pan-STARRS 7 deg^{2} field of view, the lightcurves of these guide stars can also be used to search for occultations by TNOs. The best target stars for this purpose are stars with high signal-to-noise ratio (SNR) and small angular size.In order to do this, we compiled a catalog using the SNR calculated from stars with m_V 0.5 km) ~ 2.47x10^10 deg^-2 at 95% confidence limit.
- Published
- 2010
16. The Globular Cluster System of NGC 6822
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Rolf-Peter Kudritzki, Mike Irwin, Alasdair Mackey, Jarrod R. Hurley, Patrick Côté, H. Flewelling, Nicolas F. Martin, Avon Huxor, Christopher Waters, Edouard J. Bernard, Annette M. N. Ferguson, K. C. Chambers, J. Veljanoski, W. S. Burgett, and Astronomy
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Stellar population ,Population ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,globular clusters: general ,local group ,Hubble sequence ,Photometry (optics) ,symbols.namesake ,kinematics and dynamics [galaxies] ,Astrophysics::Solar and Stellar Astrophysics ,education ,general [globular clusters] ,galaxies: kinematics and dynamics ,Astrophysics::Galaxy Astrophysics ,Physics ,education.field_of_study ,Astronomy ,Local Group ,Velocity dispersion ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,individual: NGC 6822 [galaxies] ,Globular cluster ,symbols ,Irregular galaxy ,galaxies: individual: NGC 6822 - Abstract
We present a comprehensive analysis of the globular cluster (GC) system of the Local Group dwarf irregular galaxy NGC 6822. Our study is based on homogeneous optical and near-IR photometry, as well as long-slit spectroscopic observations which are used to determine new radial velocities for 6 GCs, two of which had no previous spectroscopic information. We construct optical-near IR colour-colour diagrams and through comparison to simple stellar population models infer that the GCs have old ages consistent with being 9 Gyr or older, while their metallicities are in the range between -1.6 < [Fe/H] < -0.4. We conduct a kinematic analysis of the GC population and find tentative evidence for weak net rotation of the GC system, in the same sense as that exhibited by the underlying spheroid. The most likely amplitude of rotation is ~10 km/s, approximately half the magnitude of the observed velocity dispersion. Finally, we use the GCs to estimate the dynamical mass of NGC 6822 within 11 kpc and we formally find it to be in the range between (3-4)10^9 Msun. This implies an overall mass-to-light ratio in the range of ~ 30-40 and indicates that NGC 6822 is highly dark matter dominated. The mass and the corresponding mass-to-light ratio estimates are affected by various additional systematic effects due to limitations of the data and the model that are not necessary reflected in the formal uncertainties., 15 pages, 5 figures, 8 tables. Accepted for publication in the Monthly Notices of the Royal Astronomical Society
- Published
- 2015
17. Machine learning for transient discovery in Pan-STARRS1 difference imaging
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Paul Miller, Armin Rest, Paul A. Price, Stephen J. Smartt, W. S. Burgett, M. E. Huber, Darryl Wright, Richard J. Wainscoat, John L. Tonry, Rubina Kotak, K. C. Chambers, Nick Kaiser, Klaus W. Hodapp, Christopher Waters, K. W. Smith, H. Flewelling, Nigel Metcalfe, and Robert Jedicke
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Physics ,statistical [Methods] ,Artificial neural network ,Pixel ,general. [Supernovae] ,business.industry ,Data stream mining ,FOS: Physical sciences ,Astronomy and Astrophysics ,Machine learning ,computer.software_genre ,Random forest ,image processing surveys [Techniques] ,Support vector machine ,Space and Planetary Science ,False positive paradox ,Artificial intelligence ,False positive rate ,Astrophysics - Instrumentation and Methods for Astrophysics ,business ,data analysis [Methods] ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,computer ,Classifier (UML) - Abstract
Efficient identification and follow-up of astronomical transients is hindered by the need for humans to manually select promising candidates from data streams that contain many false positives. These artefacts arise in the difference images that are produced by most major ground-based time domain surveys with large format CCD cameras. This dependence on humans to reject bogus detections is unsustainable for next generation all-sky surveys and significant effort is now being invested to solve the problem computationally. In this paper we explore a simple machine learning approach to real-bogus classification by constructing a training set from the image data of ~32000 real astrophysical transients and bogus detections from the Pan-STARRS1 Medium Deep Survey. We derive our feature representation from the pixel intensity values of a 20x20 pixel stamp around the centre of the candidates. This differs from previous work in that it works directly on the pixels rather than catalogued domain knowledge for feature design or selection. Three machine learning algorithms are trained (artificial neural networks, support vector machines and random forests) and their performances are tested on a held-out subset of 25% of the training data. We find the best results from the random forest classifier and demonstrate that by accepting a false positive rate of 1%, the classifier initially suggests a missed detection rate of around 10%. However we also find that a combination of bright star variability, nuclear transients and uncertainty in human labelling means that our best estimate of the missed detection rate is approximately 6%., Comment: 17 pages, 16 figures, accepted for publication in MNRAS
- Published
- 2015
18. Stellar dynamics. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova
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S, Geier, F, Fürst, E, Ziegerer, T, Kupfer, U, Heber, A, Irrgang, B, Wang, Z, Liu, Z, Han, B, Sesar, D, Levitan, R, Kotak, E, Magnier, K, Smith, W S, Burgett, K, Chambers, H, Flewelling, N, Kaiser, R, Wainscoat, and C, Waters
- Abstract
Hypervelocity stars (HVSs) travel with velocities so high that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US 708. Traveling with a velocity of ~1200 kilometers per second, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVSs. Furthermore, we detected that US 708 is a fast rotator. According to our binary evolution model, it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova.
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- 2015
19. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova
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R. J. Wainscoat, Zhanwen Han, Bo Wang, Stephan Geier, W. S. Burgett, Ulrich Heber, David Levitan, E. Ziegerer, Heather Flewelling, Felix Fürst, K. C. Chambers, Branimir Sesar, Andreas Irrgang, N Kaiser, Zheng-Wei Liu, Thomas Kupfer, Christopher Waters, K. W. Smith, Eugene A. Magnier, and Rubina Kotak
- Subjects
Physics ,Multidisciplinary ,Astronomy ,Astrophysics::High Energy Astrophysical Phenomena ,Galactic Center ,White dwarf ,FOS: Physical sciences ,Astrophysics ,Escape velocity ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galaxy ,Galactic halo ,Stars ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,Hypervelocity ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
Hypervelocity stars (HVS) travel with velocities so high, that they exceed the escape velocity of the Galaxy. Several acceleration mechanisms have been discussed. Only one HVS (US 708, HVS 2) is a compact helium star. Here we present a spectroscopic and kinematic analysis of US\,708. Travelling with a velocity of $\sim1200\,{\rm km\,s^{-1}}$, it is the fastest unbound star in our Galaxy. In reconstructing its trajectory, the Galactic center becomes very unlikely as an origin, which is hardly consistent with the most favored ejection mechanism for the other HVS. Furthermore, we discovered US\,708 to be a fast rotator. According to our binary evolution model it was spun-up by tidal interaction in a close binary and is likely to be the ejected donor remnant of a thermonuclear supernova., 16 pages report, 20 pages supplementary materials
- Published
- 2015
20. Observational constraints on the catastrophic disruption rate of small main belt asteroids
- Author
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Henry H. Hsieh, J. Kleyna, John L. Tonry, H. Flewelling, Alan Fitzsimmons, Peter Vereš, Peter W. Draper, John Morgan, L. Denneau, T. Spahr, Richard J. Wainscoat, Nick Kaiser, Mikael Granvik, K. C. Chambers, Robert Jedicke, Marco Micheli, W. S. Burgett, M. E. Huber, National Land Survey of Finland, and Maanmittauslaitos
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,Absolute magnitude ,Brightness ,010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,Astronomy and Astrophysics ,Large aperture ,Astrophysics ,Object processing ,01 natural sciences ,13. Climate action ,Space and Planetary Science ,Asteroid ,0103 physical sciences ,010303 astronomy & astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,0105 earth and related environmental sciences - Abstract
We have calculated 90% confidence limits on the steady-state rate of catastrophic disruptions of main belt asteroids in terms of the absolute magnitude at which one catastrophic disruption occurs per year (HCL) as a function of the post-disruption increase in brightness (delta m) and subsequent brightness decay rate (tau). The confidence limits were calculated using the brightest unknown main belt asteroid (V = 18.5) detected with the Pan-STARRS1 (Pan-STARRS1) telescope. We measured the Pan-STARRS1's catastrophic disruption detection efficiency over a 453-day interval using the Pan-STARRS moving object processing system (MOPS) and a simple model for the catastrophic disruption event's photometric behavior in a small aperture centered on the catastrophic disruption event. Our simplistic catastrophic disruption model suggests that delta m = 20 mag and 0.01 mag d-1 < tau < 0.1 mag d-1 which would imply that H0 = 28 -- strongly inconsistent with H0,B2005 = 23.26 +/- 0.02 predicted by Bottke et al. (2005) using purely collisional models. We postulate that the solution to the discrepancy is that > 99% of main belt catastrophic disruptions in the size range to which this study was sensitive (100 m) are not impact-generated, but are instead due to fainter rotational breakups, of which the recent discoveries of disrupted asteroids P/2013 P5 and P/2013 R3 are probable examples. We estimate that current and upcoming asteroid surveys may discover up to 10 catastrophic disruptions/year brighter than V = 18.5., 61 Pages, 10 Figures, 3 Tables
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- 2015
21. Detection of a supervoid aligned with the cold spot of the cosmic microwave background
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Shaun Cole, Eugene A. Magnier, B. R. Granett, Peter W. Draper, István Szapudi, Nigel Metcalfe, Richard J. Wainscoat, András Kovács, Nick Kaiser, John L. Tonry, Paul A. Price, W. S. Burgett, Jeffrey S. Morgan, Daniel J. Farrow, Zsolt Frei, and Joseph Silk
- Subjects
Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Cold dark matter ,Infrared ,Gaussian ,Cosmic microwave background ,Cosmic background radiation ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Surveys ,Redshift ,Galaxy ,symbols.namesake ,Large-scale structure of Universe ,Space and Planetary Science ,symbols ,Astrophysics::Earth and Planetary Astrophysics ,observations [Cosmology] ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Photometric redshift - Abstract
We use the WISE-2MASS infrared galaxy catalog matched with Pan-STARRS1 (PS1) galaxies to search for a supervoid in the direction of the Cosmic Microwave Background Cold Spot. Our imaging catalog has median redshift $z\simeq 0.14$, and we obtain photometric redshifts from PS1 optical colours to create a tomographic map of the galaxy distribution. The radial profile centred on the Cold Spot shows a large low density region, extending over 10's of degrees. Motivated by previous Cosmic Microwave Background results, we test for underdensities within two angular radii, $5^\circ$, and $15^\circ$. The counts in photometric redshift bins show significantly low densities at high detection significance, $\gtrsim 5 \sigma$ and $\gtrsim 6 \sigma$, respectively, for the two fiducial radii. The line-of-sight position of the deepest region of the void is $z\simeq 0.15-0.25$. Our data, combined with an earlier measurement by Granett et al. 2010, are consistent with a large $R_{\rm void}=(220 \pm 50) h^{-1}Mpc $ supervoid with $\delta_{m} \simeq -0.14 \pm 0.04$ centered at $z=0.22\pm0.03$. Such a supervoid, constituting at least a $\simeq 3.3\sigma$ fluctuation in a Gaussian distribution of the $\Lambda CDM$ model, is a plausible cause for the Cold Spot., Comment: 8 pages, 6 figures, accepted for publication by MNRAS
- Published
- 2015
22. Cosmological constraints from measurements of Type Ia supernovae discovered during the first 1.5 yr of the Pan-STARRS1 Survey
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R. Chornock, Nick Kaiser, Klaus W. Hodapp, Daniel Scolnic, R. P. Kirshner, L. Denneau, Gautham Narayan, S. J. Smartt, Maria R. Drout, Ian Czekala, K. C. Chambers, Alicia Soderberg, A. Pastorello, S. Rodney, R. Lunnan, S. Valenti, Nigel Metcalfe, Edward F. Schlafly, C. L. Waters, Nathan Edward Sanders, Ryan J. Foley, M. T. Botticella, P. A. Price, W. M. Wood-Vasey, R. P. Kudritzki, W. S. Burgett, Edo Berger, Rubina Kotak, Christopher W. Stubbs, W. E. Sweeney, E. A. Magnier, M. E. Huber, Dan Milisavljevic, R. J. Wainscoat, Michael J. Hudson, M. McCrum, D. J. Brout, Zheng Zheng, E. Stafford, John L. Tonry, Peter W. Draper, G. H. Marion, H. Flewelling, K. W. Smith, P. Challis, D. A. Thilker, Armin Rest, Adam G. Riess, and C. Leibler
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Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,general. [Supernovae] ,Cosmic microwave background ,Cosmological parameters ,Photometric system ,FOS: Physical sciences ,Astronomy and Astrophysics ,Cosmological constant ,Astrophysics ,Type (model theory) ,Light curve ,Supernova ,13. Climate action ,Space and Planetary Science ,Dark energy ,Flatness (cosmology) ,observations [Cosmology] ,general [supernovae] ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present griz light curves of 146 spectroscopically confirmed Type Ia Supernovae ($0.03 < z, Comment: 38 pages, 16 figures, 14 tables, ApJ in press
- Published
- 2014
23. The West Texas Mesonet: A Technical Overview
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W. S. Burgett, John L. Schroeder, Arthur Doggett, K. B. Haynie, I. Sonmez, J. W. Lipe, and G. D. Skwira
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Atmospheric Science ,Meteorology ,business.industry ,Observation period ,Ocean Engineering ,Communications system ,Depth sounding ,Base station ,Phone ,Environmental science ,The Internet ,Mesonet ,Landline ,business - Abstract
The West Texas Mesonet originated in 1999 as a project of Texas Tech University. The mesonet consists of 40 automated surface meteorological stations, two atmospheric profilers, and one upper-air sounding system. Each surface station measures up to 15 meteorological and 10 agricultural parameters over an observation period of 5 and 15 min, respectively. The mesonet uses a combination of radio, cell phone, landline phone, and serial server (Internet) communication systems to relay data back to the base station at Reese Technology Center (formerly Reese Air Force Base), Texas. Data are transmitted through the radio network every 5 min for most meteorological data and every 15 min for agricultural data. For stations located outside of the radio network, phone systems transmit data every 30–60 min. The archive includes data received through the various communication systems, as well as data downloaded in the field from each station during regularly scheduled maintenance visits. Quality assurance/control (QA/QC) tests effectively flag data for manual review from a decision maker. The QA/QC flags and review decisions are then added to the database. All data are available free of charge; real-time data are available on the West Texas Mesonet Web page, and an interface to access the data archive is currently being developed.
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- 2005
24. Design of the Pan-STARRS telescopes
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Edward J. Mannery, Richard J. Wainscoat, Klaus-Werner Hodapp, Uwe Laux, T. Dombeck, K. C. Chambers, C. Hude, John L. Tonry, Nick Kaiser, Mark Waterson, J. N. Heasley, D. Hafner, István Szapudi, P. A. Price, S. Isani, David G. Monet, J. Hoblitt, Peter M. Onaka, Alan Ryan, Robert H. Lupton, David Jewitt, Walter A. Siegmund, John Morgan, M. Chun, Michael Maberry, Robert Jedicke, A. Douglas, Herve Aussel, Eugene A. Magnier, W. S. Burgett, and G. A. Luppino
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Physics ,Telescope ,Space and Planetary Science ,law ,Potentially hazardous object ,Astronomy ,Astronomy and Astrophysics ,Large Synoptic Survey Telescope ,Wide field ,law.invention ,Remote sensing - Abstract
Pan-STARRS, the Panoramic Survey Telescope and Rapid Response System, is a project by the Institute for Astronomy, University of Hawaii, to first develop a single wide field synoptic survey telescope (Pan-STARRS-1) followed by a system of four such telescopes. It is designed to accomplish many of the science goals envisioned by the Decadal Review for the Large Synoptic Survey Telescope (LSST). The primary mission of Pan-STARRS is the detection of potentially hazardous asteroids (PHA), secondary science objectives are a (nearly) all-sky survey, a medium-deep survey, an ultra-deep survey, and studies of transients and variable objects. This paper presents the current status of the telescope system design, with emphasis on the optics. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
- Published
- 2004
25. Optical Confirmation and Redshift Estimation of the Planck Cluster Candidates overlapping the Pan-STARRS Survey
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Christopher W. Stubbs, Paul A. Price, Jiayi Liu, Ben Hoyle, Nigel Metcalfe, Shantanu Desai, Johannes Koppenhoefer, C. Hennig, Christopher Waters, John Morgan, W. S. Burgett, Shaun Cole, Joseph J. Mohr, Nick Kaiser, Peter W. Draper, Richard J. Wainscoat, K. C. Chambers, John L. Tonry, and K. Paech
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,clusters: general [Galaxies] ,01 natural sciences ,symbols.namesake ,Large-scale structure of Universe ,0103 physical sciences ,Planck ,010303 astronomy & astrophysics ,Galaxy cluster ,Astrophysics::Galaxy Astrophysics ,Physics ,010308 nuclear & particles physics ,Astronomy ,Astronomy and Astrophysics ,Type-cD galaxy ,Galactic plane ,Redshift survey ,Catalogues ,Galaxy ,Redshift ,Stars ,Space and Planetary Science ,symbols ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We report results of a study of Planck Sunyaev-Zel'dovich effect (SZE) selected galaxy cluster candidates using the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) imaging data. We first examine 150 Planck confirmed galaxy clusters with spectroscopic redshifts to test our algorithm for identifying optical counterparts and measuring their redshifts; our redshifts have a typical accuracy of $��_{z/(1+z)} \sim 0.022$ for this sample. Using 60 random sky locations, we estimate that our chance of contamination through a random superposition is ~ 3 per cent. We then examine an additional 237 Planck galaxy cluster candidates that have no redshift in the source catalogue. Of these 237 unconfirmed cluster candidates we are able to confirm 60 galaxy clusters and measure their redshifts. A further 83 candidates are so heavily contaminated by stars due to their location near the Galactic plane that we do not attempt to identify counterparts. For the remaining 94 candidates we find no optical counterpart but use the depth of the Pan-STARRS1 data to estimate a redshift lower limit $z_{\text{lim}(10^{15})}$ beyond which we would not have expected to detect enough galaxies for confirmation. Scaling from the already published Planck sample, we expect that $\sim$12 of these unconfirmed candidates may be real clusters., 11 pages, 9 figures
- Published
- 2014
26. Discovery of eight z ~ 6 quasars from Pan-STARRS1
- Author
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Jeffrey S. Morgan, Bram Venemans, A. Weiß, H-W. Rix, Xiaohui Fan, R.-P. Kudritzki, Fabian Walter, Christopher Waters, Eduardo Bañados, W. S. Burgett, Eric Morganson, Eugene A. Magnier, W. E. Sweeney, John L. Tonry, Linhua Jiang, Nigel Metcalfe, Roberto Decarli, Emanuele Paolo Farina, R. Simcoe, G. De Rosa, Paul A. Price, Richard J. Wainscoat, Nick Kaiser, K. C. Chambers, Christopher W. Stubbs, Jochen Greiner, and Ian D. McGreer
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,law.invention ,Telescope ,emission lines [Quasars] ,law ,Emission spectrum ,education ,observations [Cosmology] ,Astrophysics::Galaxy Astrophysics ,Line (formation) ,Physics ,education.field_of_study ,Supermassive black hole ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy and Astrophysics ,Quasar ,general [Quasars] ,Astrophysics - Astrophysics of Galaxies ,Redshift ,13. Climate action ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Surveys ,Equivalent width ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
High-redshift quasars are currently the only probes of the growth of supermassive black holes and potential tracers of structure evolution at early cosmic time. Here we present our candidate selection criteria from the Panoramic Survey Telescope & Rapid Response System 1 and follow-up strategy to discover quasars in the redshift range 5.75.7 by more than 10%. We additionally recovered 18 previously known quasars. The eight quasars presented here span a large range of luminosities (-27.3 < M_{1450} < -25.4; 19.6 < z_ps1 < 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show a weak or no Ly$\alpha$ emission line (25% with rest-frame equivalent width of the Ly$\alpha$ + Nv line lower than 15{\AA}). We find a larger fraction of weak-line emission quasars than in lower redshift studies. This may imply that the weak-line quasar population at the highest redshifts could be more abundant than previously thought. However, larger samples of quasars are needed to increase the statistical significance of this finding., Comment: AJ in press, 16 pages, 5 figures, 7 tables
- Published
- 2014
27. An optimized Method to Identify RR Lyrae stars in the SDSS X Pan-STARRS1 Overlapping Area Using a Bayesian Generative Technique
- Author
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M. E. Huber, Nicolas F. Martin, Christopher Waters, Nick Kaiser, Mohamad Abbas, W. S. Burgett, and Eva K. Grebel
- Subjects
Physics ,media_common.quotation_subject ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,RR Lyrae variable ,Light curve ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Stars ,13. Climate action ,Space and Planetary Science ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,Statistics ,Astrophysics::Solar and Stellar Astrophysics ,Halo ,Astrophysics::Earth and Planetary Astrophysics ,Variable star ,Main sequence ,Astrophysics::Galaxy Astrophysics ,media_common - Abstract
We present a method for selecting RR Lyrae (RRL) stars (or other type of variable stars) in the absence of a large number of multi-epoch data and light curve analyses. Our method uses color and variability selection cuts that are defined by applying a Gaussian Mixture Bayesian Generative Method (GMM) on 636 pre-identified RRL stars instead of applying the commonly used rectangular cuts. Specifically, our method selects 8,115 RRL candidates (heliocentric distances < 70 kpc) using GMM color cuts from the Sloan Digital Sky Survey (SDSS) and GMM variability cuts from the Panoramic Survey Telescope and Rapid Response System 1 3pi survey (PS1). Comparing our method with the Stripe 82 catalog of RRL stars shows that the efficiency and completeness levels of our method are ~77% and ~52%, respectively. Most contaminants are either non-variable main-sequence stars or stars in eclipsing systems. The method described here efficiently recovers known stellar halo substructures. It is expected that the current completeness and efficiency levels will further improve with the additional PS1 epochs (~3 epochs per filter) that will be observed before the conclusion of the survey. A comparison between our efficiency and completeness levels using the GMM method to the efficiency and completeness levels using rectangular cuts that are commonly used yielded a significant increase in the efficiency level from ~13% to ~77% and an insignificant change in the completeness levels. Hence, we favor using the GMM technique in future studies. Although we develop it over the SDSS X PS1 footprint, the technique presented here would work well on any multi-band, multi-epoch survey for which the number of epochs is limited., 10 pages, 10 figures. Accepted 2014 April 23
- Published
- 2014
28. The superluminous supernova PS1-11ap: bridging the gap between low and high redshift
- Author
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Christopher W. Stubbs, Klaus-Werner Hodapp, Rolf-Peter Kudritzki, Stefano Valenti, Richard J. Wainscoat, W. E. Sweeney, S. J. Smartt, K. C. Chambers, Dan Milisavljevic, Matt Nicholl, K. W. Smith, Armin Rest, D. A. Howell, Adam G. Riess, Anders Jerkstrand, Maria R. Drout, Cosimo Inserra, Morgan Fraser, Paul A. Price, T. W. Chen, Ryan J. Foley, M. McCrum, W. S. Burgett, M. E. Huber, Ian Czekala, Nick Kaiser, S. Rodney, David Young, Eugene A. Magnier, Nigel Metcalfe, M. T. Botticella, Rubina Kotak, John L. Tonry, H. Flewelling, Edo Berger, Ryan Chornock, Fabio Bresolin, Peter W. Draper, A. Pastorello, Darryl Wright, and W. M. Wood-Vasey
- Subjects
individual: PS1-11ap [Supernovae] ,Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,general [Supernovae] ,Astronomy ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Magnetar ,01 natural sciences ,Instability ,Redshift ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Extensive data ,Pair-instability supernova ,010306 general physics ,Astrophysics - High Energy Astrophysical Phenomena ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present optical photometric and spectroscopic coverage of the superluminous supernova (SLSN) PS1-11ap, discovered with the Pan-STARRS1 Medium Deep Survey at z = 0.524. This intrinsically blue transient rose slowly to reach a peak magnitude of M_u = -21.4 mag and bolometric luminosity of 8 x 10^43 ergs^-1 before settling onto a relatively shallow gradient of decline. The observed decline is significantly slower than those of the superluminous type Ic SNe which have been the focus of much recent attention. Spectroscopic similarities with the lower redshift SN2007bi and a decline rate similar to 56Co decay timescale initially indicated that this transient could be a candidate for a pair instability supernova (PISN) explosion. Overall the transient appears quite similar to SN2007bi and the lower redshift object PTF12dam. The extensive data set, from 30 days before peak to 230 days after, allows a detailed and quantitative comparison with published models of PISN explosions. We find that the PS1-11ap data do not match these model explosion parameters well, supporting the recent claim that these SNe are not pair instability explosions. We show that PS1-11ap has many features in common with the faster declining superluminous Ic supernovae and the lightcurve evolution can also be quantitatively explained by the magnetar spin down model. At a redshift of z = 0.524 the observer frame optical coverage provides comprehensive restframe UV data and allows us to compare it with the superluminous SNe recently found at high redshifts between z = 2-4. While these high-z explosions are still plausible PISN candidates, they match the photometric evolution of PS1-11ap and hence could be counterparts to this lower redshift transient., 19 pages, 10 figures, Accepted for publication in MNRAS
- Published
- 2014
29. Newly Discovered RR Lyrae Stars in the SDSSXPanXSTARRS1XCatalina Footprint
- Author
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M. A. Abbas, Nicolas F. Martin, H. Flewelling, Eva K. Grebel, Richard J. Wainscoat, and W. S. Burgett
- Subjects
Physics ,media_common.quotation_subject ,Astronomy ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,RR Lyrae variable ,Light curve ,Astrophysics - Astrophysics of Galaxies ,law.invention ,Galactic halo ,Telescope ,Stars ,13. Climate action ,Space and Planetary Science ,law ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,Galaxy formation and evolution ,Halo ,media_common - Abstract
We present the detection of 6,371 RR Lyrae (RRL) stars distributed across ~14,000 deg^2 of the sky from the combined data of the Sloan Digital Sky Survey (SDSS), the Panoramic Survey Telescope and Rapid Response System 1 (PS1), and the second photometric catalogue from the Catalina Survey (CSDR2), out of these, ~2,021 RRL stars (~572 RRab and 1,449 RRc) are new discoveries. The RRL stars have heliocentric distances in the 4--28 kpc distance range. RRL-like color cuts from the SDSS and variability cuts from the PS1 are used to cull our candidate list. We then use the CSDR2 multi-epoch data to refine our sample. Periods were measured using the Analysis of Variance technique while the classification process is performed with the Template Fitting Method in addition to the visual inspection of the light curves. A cross-match of our RRL star discoveries with previous published catalogs of RRL stars yield completeness levels of ~50% for both RRab and RRc stars, and an efficiency of ~99% and ~87% for RRab and RRc stars, respectively. We show that our method for selecting RRL stars allows us to recover halo structures. The full lists of all the RRL stars are made publicly available., Comment: 14 pages, 11 figures. Accepted 2014 March 30. Received 2014 March 12; in original form 2013 November 28
- Published
- 2014
- Full Text
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30. Measuring Quasar Variability with Pan-STARRS1 and SDSS
- Author
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Edward F. Schlafly, Paul J. Green, John L. Tonry, E. Morganson, K. C. Chambers, W. S. Burgett, Eugene A. Magnier, Nick Kaiser, Philip J. Marshall, Paul A. Price, H. W. Rix, John Morgan, and Fabian Walter
- Subjects
Physics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,media_common.quotation_subject ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Power law ,Redshift ,Red shift ,Root mean square ,13. Climate action ,Space and Planetary Science ,Sky ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics ,Spectroscopy ,Time range ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,media_common - Abstract
We measure quasar variability using the Panoramic Survey Telescope and Rapid Response System 1 Survey (Pan-STARRS1 or PS1) and the Sloan Digital Sky Survey (SDSS) and establish a method of selecting quasars via their variability in 10{sup 4} deg{sup 2} surveys. We use 10{sup 5} spectroscopically confirmed quasars that have been well measured in both PS1 and SDSS and take advantage of the decadal timescales that separate SDSS measurements and PS1 measurements. A power law model fits the data well over the entire time range tested, 0.01-10 yr. Variability in the current PS1-SDSS data set can efficiently distinguish between quasars and nonvarying objects. It improves the purity of a griz quasar color cut from 4.1% to 48% while maintaining 67% completeness. Variability will be very effective at finding quasars in data sets with no u band and in redshift ranges where exclusively photometric selection is not efficient. We show that quasars' rest-frame ensemble variability, measured as a root mean squared in Δ magnitudes, is consistent with V(z, L, t) = A {sub 0}(1 + z){sup 0.37}(L/L {sub 0}){sup –0.16}(t/1 yr){sup 0.246}, where L {sub 0} = 10{sup 46} erg s{sup –1} and A {sub 0} = 0.190, 0.162, 0.147, ormore » 0.141 in the g {sub P1}, r {sub P1}, i {sub P1}, or z {sub P1}filter, respectively. We also fit across all four filters and obtain median variability as a function of z, L, and λ as V(z, L, λ, t) = 0.079(1 + z){sup 0.15}(L/L {sub 0}){sup –0.2}(λ/1000 nm){sup –0.44}(t/1 yr){sup 0.246}.« less
- Published
- 2014
- Full Text
- View/download PDF
31. Slowly fading super-luminous supernovae that are not pair-instability explosions
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K. C. Chambers, Ting-Wan Chen, Paul A. Price, Raffaella Margutti, Armin Rest, Adam G. Riess, S. Rodney, Enrico Cappellaro, Francesco Taddia, Anders Jerkstrand, K. W. Smith, Christopher W. Stubbs, Giorgos Leloudas, Seppo Mattila, M. E. Huber, Jesper Sollerman, Stuart A. Sim, Stephen J. Smartt, Erkki Kankare, Daniel Scolnic, Stefano Benetti, Ragnhild Lunnan, Cosimo Inserra, Suvi Gezari, D. A. Howell, David Young, Nick Kaiser, Nigel Metcalfe, Darryl Wright, Yuji Urata, Fabio Bresolin, John L. Tonry, Ryan J. Foley, Alicia M. Soderberg, Gautham Narayan, W. E. Sweeney, H. Flewelling, A. Morales-Garoffolo, Andrea Pastorello, M. McCrum, Matt Nicholl, W. M. Wood-Vasey, W. S. Burgett, L. Tomasella, Rolf-Peter Kudritzki, Robert P. Kirshner, Dan Milisavljevic, Nathan Edward Sanders, Tuomas Kangas, Morgan Fraser, John Morgan, Stefano Valenti, Nancy Elias-Rosa, Ryan Chornock, M. T. Botticella, Edo Berger, Rubina Kotak, Christopher Waters, Eugene A. Magnier, and S. Taubenberger
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Metallicity ,media_common.quotation_subject ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,7. Clean energy ,Luminosity ,0103 physical sciences ,Gravitational collapse ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,media_common ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Solar mass ,Multidisciplinary ,ta115 ,010308 nuclear & particles physics ,Astronomy ,Galaxy ,Redshift ,Universe ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Super-luminous supernovae that radiate more than 10^44 ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-30 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of 56Ni are synthesized; this isotope decays to 56Fe via 56Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6x10^-6 times that of the core-collapse rate., Originally published in Nature, Oct 2013. Updated Oct 2016 to correct an error
- Published
- 2013
32. Systematic Uncertainties Associated with the Cosmological Analysis of the First Pan-STARRS1 Type Ia Supernova Sample
- Author
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Christopher M. Waters, Christopher W. Stubbs, I. Czekal, E. Stafford, M. E. Huber, Ryan J. Foley, Peter W. Draper, Stephen J. Smartt, R. Chornock, P. A. Price, L. Denneau, R. P. Kirshner, M. T. Botticella, M. McCrum, Maria R. Drout, Dan Milisavljevic, Rubina Kotak, Armin Rest, S. Valenti, Nathan Edward Sanders, Ragnhild Lunnan, Daniel Scolnic, S. Rodney, P. Challis, Michael J. Hudson, Zheng Zheng, Edward F. Schlafly, Nigel Metcalfe, Adam G. Riess, G. H. Marion, Edo Berger, E. A. Magnier, D. Brout, R. P. Kudritzki, W. S. Burgett, K. C. Chambers, R. J. Wainscoat, K. W. Smith, Nick Kaiser, Klaus W. Hodapp, Gautham Narayan, A. Pastorello, David A. Thilker, W. M. Wood-Vasey, W. E. Sweeney, Alicia Soderberg, John L. Tonry, H. Flewelling, and C. Leibler
- Subjects
Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,general. [Supernovae] ,Cosmic microwave background ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Type (model theory) ,CMB cold spot ,Omega ,Galaxy ,Supernova ,symbols.namesake ,13. Climate action ,Space and Planetary Science ,Dark energy ,symbols ,Planck ,Flatness (cosmology) ,general [supernovae] ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We probe the systematic uncertainties from 113 Type Ia supernovae (SNIa) in the Pan-STARRS1 (PS1) sample along with 197 SN Ia from a combination of low-redshift surveys. The companion paper by Rest et al. (2013) describes the photometric measurements and cosmological inferences from the PS1 sample. The largest systematic uncertainty stems from the photometric calibration of the PS1 and low-z samples. We increase the sample of observed Calspec standards from 7 to 10 used to define the PS1 calibration system. The PS1 and SDSS-II calibration systems are compared and discrepancies up to ~0.02 mag are recovered. We find uncertainties in the proper way to treat intrinsic colors and reddening produce differences in the recovered value of w up to 3%. We estimate masses of host galaxies of PS1 supernovae and detect an insignificant difference in distance residuals of the full sample of 0.037\pm0.031 mag for host galaxies with high and low masses. Assuming flatness in our analysis of only SNe measurements, we find $w = {-1.120^{+0.360}_{-0.206}\textrm{(Stat)} ^{+0.269}_{-0.291}\textrm{(Sys)}}$. With additional constraints from BAO, CMB(Planck) and H0 measurements, we find $w = -1.166^{+0.072}_{-0.069}$ and $\Omega_M=0.280^{+0.013}_{-0.012}$ (statistical and systematic errors added in quadrature). Significance of the inconsistency with $w=-1$ depends on whether we use Planck or WMAP measurements of the CMB: $w_{\textrm{BAO+H0+SN+WMAP}}=-1.124^{+0.083}_{-0.065}$., Comment: 24 pages, 20 figures. Accepted by ApJ
- Published
- 2013
33. Stacked reverberation mapping
- Author
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Ryan Chornock, Tom Shanks, Brandon C. Kelly, Scott M. Croom, Rachel L. Webster, Nick Kaiser, Edo Berger, K. C. Chambers, S. Fine, W. S. Burgett, Paul A. Price, and Paul J. Green
- Subjects
Physics ,Seyfert. [Galaxies] ,Supermassive black hole ,Active galactic nucleus ,active [Galaxies] ,Radio galaxy ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Quasar ,general [Quasars] ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Redshift ,Luminosity ,emission lines [Quasars] ,Space and Planetary Science ,Reverberation mapping ,Emission spectrum ,Astrophysics::Galaxy Astrophysics - Abstract
Over the past 20 years reverberation mapping has proved one of the most successful techniques for studying the local ( 0.1, or for the more-luminous quasars that make up the majority of current spectroscopic samples, or for rest-frame ultraviolet emission lines available in optical spectra of z > 0.5 objects. Previously, we described a technique for stacking cross-correlations to obtain reverberation mapping results at high z. Here, we present the first results from a campaign designed for this purpose. We construct stacked cross-correlation functions for the C IV and Mg II lines and find a clear peak in both. We find that the peak in the Mg II correlation is at longer lags than C IV consistent with previous results at low redshift. For the C IV sample, we are able to bin by luminosity and find evidence for increasing lags for more-luminous objects. This C IV radius–luminosity relation is consistent with previous studies but with a fraction of the observational cost.
- Published
- 2013
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34. PS1-10afx AT
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R. Chornock, E. Berger, A. Rest, D. Milisavljevic, R. Lunnan, R. J. Foley, A. M. Soderberg, S. J. Smartt, A. J. Burgasser, P. Challis, L. Chomiuk, I. Czekala, M. Drout, W. Fong, M. E. Huber, R. P. Kirshner, C. Leibler, B. McLeod, G. H. Marion, G. Narayan, A. G. Riess, K. C. Roth, N. E. Sanders, D. Scolnic, K. Smith, C. W. Stubbs, J. L. Tonry, S. Valenti, W. S. Burgett, K. C. Chambers, K. W. Hodapp, N. Kaiser, R.-P. Kudritzki, E. A. Magnier, and P. A. Price
- Published
- 2013
35. Super Luminous Ic Supernovae: catching a magnetar by the tail
- Author
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T. W. Chen, M. E. Huber, D. H. Wright, C. L. Waters, Matt Nicholl, Giorgos Leloudas, L. Magill, Anders Jerkstrand, F. Taddia, P. A. Price, Mattias Ergon, M. T. Botticella, J. P. U. Fynbo, Nigel Metcalfe, Jesper Sollerman, K. C. Chambers, W. Sweeney, R. P. Kudritzki, W. S. Burgett, S. Valenti, Morgan Fraser, M. G. McCrumm, A. Pastorello, S. Geier, John L. Tonry, C. Inserra, Armin Rest, D. A. Howell, Rubina Kotak, S. Taubenberger, H. Flewelling, S. J. Smartt, S. Benetti, E. A. Magnier, R. J. Wainscoat, K. W. Smith, D. R. Young, F. Bresolin, Nick Kaiser, and Klaus W. Hodapp
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,general [Supernovae] ,FOS: Physical sciences ,Astrophysics ,Type (model theory) ,Magnetar ,01 natural sciences ,7. Clean energy ,Luminosity ,magnetars [Stars] ,Astronomi, astrofysik och kosmologi ,0103 physical sciences ,Astronomy, Astrophysics and Cosmology ,PTF11rks ,Emission spectrum ,Ejecta ,SN 2012il) ,010303 astronomy & astrophysics ,Physics ,SN 2011ke ,High Energy Astrophysical Phenomena (astro-ph.HE) ,SN 2011kf ,010308 nuclear & particles physics ,individual (PTF10hgi [Supernovae] ,Astronomy and Astrophysics ,Galaxy ,Redshift ,Supernova ,13. Climate action ,Space and Planetary Science ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We report extensive observational data for five of the lowest redshift Super-Luminous Type Ic Supernovae (SL-SNe Ic) discovered to date, namely PTF10hgi, SN2011ke, PTF11rks, SN2011kf and SN2012il. Photometric imaging of the transients at +50 to +230 days after peak combined with host galaxy subtraction reveals a luminous tail phase for four of these SL-SNe. A high resolution, optical and near infrared spectrum from xshooter provides detection of a broad He I $\lambda$10830 emission line in the spectrum (+50d) of SN2012il, revealing that at least some SL-SNe Ic are not completely helium free. At first sight, the tail luminosity decline rates that we measure are consistent with the radioactive decay of \co, and would require 1-4M of \ni to produce the luminosity. These \ni masses cannot be made consistent with the short diffusion times at peak, and indeed are insufficient to power the peak luminosity. We instead favour energy deposition by newborn magnetars as the power source for these objects. A semi-analytical diffusion model with energy input from the spin-down of a magnetar reproduces the extensive lightcurve data well. The model predictions of ejecta velocities and temperatures which are required are in reasonable agreement with those determined from our observations. We derive magnetar energies of $0.4\lesssim E$($10^{51}$erg) $\lesssim6.9$ and ejecta masses of $2.3\lesssim M_{ej}$(\M) $\lesssim 8.6$. The sample of five SL-SNe Ic presented here, combined with SN 2010gx - the best sampled SL-SNe Ic so far - point toward an explosion driven by a magnetar as a viable explanation for all SL-SNe Ic., Comment: 34 pages, 19 figures, accepted by ApJ. 1 figure added and some sections have been reorganised with respect to the previous version
- Published
- 2013
- Full Text
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36. A Pan-STARRS1 View of the Bifurcated Sagittarius Stream
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C. T. Slater, E. F. Bell, E. F. Schlafly, M. Jurić, N. F. Martin, H.-W. Rix, E. J. Bernard, W. S. Burgett, K. C. Chambers, D. P. Finkbeiner, B. Goldman, N. Kaiser, E. A. Magnier, E. P. Morganson, P. A. Price, and J. L. Tonry
- Subjects
Physics ,010308 nuclear & particles physics ,media_common.quotation_subject ,Northern Hemisphere ,Astrophysics::Instrumentation and Methods for Astrophysics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Sagittarius Stream ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Orbit ,Space and Planetary Science ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,010303 astronomy & astrophysics ,Red clump ,Sagittarius ,Astrophysics::Galaxy Astrophysics ,media_common - Abstract
We use data from the Pan-STARRS1 survey to present a panoramic view of the Sagittarius tidal stream in the southern Galactic hemisphere. As a result of the extensive sky coverage of Pan-STARRS1, the southern stream is visible along more than 60 degrees of its orbit, nearly double the length seen by the SDSS. The recently discovered southern bifurcation of the stream is also apparent, with the fainter branch of the stream visible over at least 30 degrees. Using a combination of fitting both the main sequence turn-off and the red clump, we measure the distance to both arms of the stream in the south. We find that the distances to the bright arm of the stream agree very well with the N-body models of Law & Majewski (2010). We also find that the faint arm lies ~5 kpc closer to the Sun than the bright arm, similar to the behavior seen in the northern hemisphere., Accepted to ApJ. 10 pages, 8 figures
- Published
- 2012
37. Correction: Corrigendum: Slowly fading super-luminous supernovae that are not pair-instability explosions
- Author
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Christopher W. Stubbs, Jesper Sollerman, M. McCrum, S. Valenti, Dan Milisavljevic, K. C. Chambers, E. A. Magnier, A. Morales-Garoffolo, Matt Nicholl, Nick Kaiser, Francesco Taddia, P. A. Price, S. J. Smartt, Giorgos Leloudas, S. Benetti, Seppo Mattila, Ting-Wan Chen, Morgan Fraser, David Young, R. P. Kudritzki, W. S. Burgett, Gautham Narayan, Alicia Soderberg, Enrico Cappellaro, Christopher M. Waters, R. Lunnan, L. Tomasella, Suvi Gezari, K. W. Smith, Yuji Urata, Anders Jerkstrand, S. Rodney, Edo Berger, Erkki Kankare, M. T. Botticella, Nigel Metcalfe, Ryan J. Foley, W. M. Wood-Vasey, John L. Tonry, M. E. Huber, David W. Wright, H. Flewelling, R. Chornock, C. Inserra, Daniel Scolnic, Nancy Elias-Rosa, Armin Rest, D. A. Howell, Rubina Kotak, Adam G. Riess, W. E. Sweeney, S. Taubenberger, Stuart A. Sim, A. Pastorello, R. P. Kirshner, F. Bresolin, T. Kangas, John Morgan, Nathan Edward Sanders, and R. Margutti
- Subjects
Physics ,Multidisciplinary ,Swift Gamma-Ray Burst Mission ,010308 nuclear & particles physics ,High-energy astronomy ,Astronomy ,Astrophysics ,Light curve ,01 natural sciences ,Instability ,Photometry (optics) ,Stars ,Supernova ,0103 physical sciences ,Fading ,010303 astronomy & astrophysics - Abstract
Nature 502, 346–349 (2013); doi:10.1038/nature12569 In this Letter, we have identified an important error affecting Fig. 4 and Extended Data Fig. 6, as well as the values of some parameters derived from our model fits. We stress that this error in no way affects the discussion or the conclusions. Inbuilding the bolometric light curve of the superluminous supernova PTF 12dam, our code assumed that photometry from the Swift satellite was calibrated in the Vega magnitude system.
- Published
- 2016
38. FINDING, CHARACTERIZING, AND CLASSIFYING VARIABLE SOURCES IN MULTI-EPOCH SKY SURVEYS: QSOs AND RR LYRAE IN PS1 3πDATA
- Author
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Branimir Sesar, Željko Ivezić, Klaus-Werner Hodapp, Nigel Metcalfe, Eric F. Bell, Nicolas F. Martin, Nina Hernitschek, Edward F. Schlafly, Eugene A. Magnier, Nick Kaiser, Christopher Waters, Richard J. Wainscoat, Eva K. Grebel, H. Flewelling, David W. Hogg, W. S. Burgett, Hans-Walter Rix, Observatoire astronomique de Strasbourg (ObAS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
QSOS ,astro-ph.GA ,media_common.quotation_subject ,statistical [methods] ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astronomy & Astrophysics ,RR Lyrae variable ,Atomic ,Physical Chemistry ,01 natural sciences ,variables: RR Lyrae [stars] ,Particle and Plasma Physics ,0103 physical sciences ,Nuclear ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,ComputingMilieux_MISCELLANEOUS ,media_common ,Physics ,Ground truth ,general [quasars] ,010308 nuclear & particles physics ,Molecular ,Astronomy and Astrophysics ,Galactic plane ,Light curve ,Astrophysics - Astrophysics of Galaxies ,Random forest ,Amplitude ,[SDU]Sciences of the Universe [physics] ,Space and Planetary Science ,Sky ,Astronomical and Space Sciences ,Physical Chemistry (incl. Structural) - Abstract
In area and depth, the Pan-STARRS1 (PS1) 3$\pi$ survey is unique among many-epoch, multi-band surveys and has enormous potential for all-sky identification of variable sources. PS1 has observed the sky typically seven times in each of its five bands ($grizy$) over 3.5 years, but unlike SDSS not simultaneously across the bands. Here we develop a new approach for quantifying statistical properties of non-simultaneous, sparse, multi-color lightcurves through light-curve structure functions, effectively turning PS1 into a $\sim 35$-epoch survey. We use this approach to estimate variability amplitudes and timescales $(\omega_r, \tau)$ for all point-sources brighter than $r_{\mathrm{P1}}=21.5$ mag in the survey. With PS1 data on SDSS Stripe 82 as ``ground truth", we use a Random Forest Classifier to identify QSOs and RR Lyrae based on their variability and their mean PS1 and WISE colors. We find that, aside from the Galactic plane, QSO and RR Lyrae samples of purity $\sim$75\% and completeness $\sim$92\% can be selected. On this basis we have identified a sample of $\sim 1,000,000$ QSO candidates, as well as an unprecedentedly large and deep sample of $\sim$150,000 RR Lyrae candidates with distances from $\sim$10 kpc to $\sim$120 kpc. Within the Draco dwarf spheroidal, we demonstrate a distance precision of 6\% for RR Lyrae candidates. We provide a catalog of all likely variable point sources and likely QSOs in PS1, a total of $25.8\times 10^6$ sources.
- Published
- 2016
39. An ultraviolet\u2013optical flare from the tidal disruption of a helium-rich stellar core
- Author
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Alicia M. Soderberg, Christopher W. Stubbs, K. C. Chambers, Gautham Narayan, Edo Berger, Ryan J. Foley, M. E. Huber, Karl Forster, G. H. Marion, Ryan Chornock, K. W. Smith, Peter Challis, Timothy M. Heckman, Rolf-Peter Kudritzki, Andy Lawrence, Daniel Scolnic, Nick Kaiser, Stephen J. Smartt, Suvi Gezari, Paul A. Price, T. Grav, John Morgan, W. M. Wood-Vasey, Eugene A. Magnier, D. C. Martin, Laura Chomiuk, John L. Tonry, Colin Norman, Armin Rest, Adam G. Riess, Robert P. Kirshner, J. N. Heasley, James D. Neill, and W. S. Burgett
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,law.invention ,Tidal disruption event ,law ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,Debris disk ,Supermassive black hole ,Solar mass ,Multidisciplinary ,010308 nuclear & particles physics ,Astronomy ,Light curve ,Galaxy ,Accretion (astrophysics) ,Astrophysics::Earth and Planetary Astrophysics ,Flare ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The flare of radiation from the tidal disruption and accretion of a star can be used as a marker for supermassive black holes that otherwise lie dormant and undetected in the centres of distant galaxies. Previous candidate flares have had declining light curves in good agreement with expectations, but with poor constraints on the time of disruption and the type of star disrupted, because the rising emission was not observed. Recently, two `relativistic' candidate tidal disruption events were discovered, each of whose extreme X-ray luminosity and synchrotron radio emission were interpreted as the onset of emission from a relativistic jet. Here we report the discovery of a luminous ultraviolet-optical flare from the nuclear region of an inactive galaxy at a redshift of 0.1696. The observed continuum is cooler than expected for a simple accreting debris disk, but the well-sampled rise and decline of its light curve follows the predicted mass accretion rate, and can be modelled to determine the time of disruption to an accuracy of two days. The black hole has a mass of about 2 million solar masses, modulo a factor dependent on the mass and radius of the star disrupted. On the basis of the spectroscopic signature of ionized helium from the unbound debris, we determine that the disrupted star was a helium-rich stellar core., Comment: To appear in Nature on May 10, 2012
- Published
- 2012
40. Ultra-Luminous Supernovae as a New Probe of the Interstellar Medium in Distant Galaxies
- Author
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E. Berger, R. Chornock, R. Lunnan, R. Foley, I. Czekala, A. Rest, C. Leibler, A. M. Soderberg, K. Roth, G. Narayan, M. E. Huber, D. Milisavljevic, N. E. Sanders, M. Drout, R. Margutti, R. P. Kirshner, G. H. Marion, P. J. Challis, A. G. Riess, S. J. Smartt, W. S. Burgett, K. W. Hodapp, J. N. Heasley, N. Kaiser, R.-P. Kudritzki, E. A. Magnier, M. McCrum, P. A. Price, K. Smith, J. L. Tonry, and R. J. Wainscoat
- Subjects
Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,010504 meteorology & atmospheric sciences ,Stellar mass ,Stellar population ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Redshift ,Galaxy ,Interstellar medium ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Gamma-ray burst ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present the Pan-STARRS1 discovery and light curves, and follow-up MMT and Gemini spectroscopy of an ultra-luminous supernova (ULSN; dubbed PS1-11bam) at a redshift of z=1.566 with a peak brightness of M_UV=-22.3 mag. PS1-11bam is one of the highest redshift spectroscopically-confirmed SNe known to date. The spectrum is characterized by broad absorption features typical of previous ULSNe (e.g., CII, SiIII), and by strong and narrow MgII and FeII absorption lines from the interstellar medium (ISM) of the host galaxy, confirmed by an [OII]3727 emission line at the same redshift. The equivalent widths of the FeII2600 and MgII2803 lines are in the top quartile of the quasar intervening absorption system distribution, but are weaker than those of gamma-ray burst intrinsic absorbers (i.e., GRB host galaxies). We also detect the host galaxy in pre-explosion Pan-STARRS1 data and find that its UV spectral energy distribution is best fit with a young stellar population age of tau~15-45 Myr and a stellar mass of M \sim (1.1-2.6)x10^9 M_sun (for Z=0.05-1 Z_sun). The star formation rate inferred from the UV continuum and [OII]3727 emission line is ~10 M_sun/yr, higher than in any previous ULSN host. PS1-11bam provides the first direct demonstration that ULSNe can serve as probes of the interstellar medium in distant galaxies. At the present, the depth and red sensitivity of PS1 are uniquely suited to finding such events at cosmologically interesting redshifts (z~1-2); the future combination of LSST and 30-m class telescopes promises to extend this technique to z~4., Comment: Submitted to ApJL; 9 pages; 4 figures; 1 table
- Published
- 2012
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41. Pan-STARRS1 Discovery of Two Ultraluminous Supernovae at z ≈ 0.9
- Author
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Alicia M. Soderberg, Kathy Roth, M. E. Huber, Gautham Narayan, Edo Berger, Ian Czekala, Christopher W. Stubbs, Armin Rest, Adam G. Riess, R. P. Kudritzki, John Morgan, W. S. Burgett, Nathan Edward Sanders, S. J. Smartt, Laura Chomiuk, P. A. Price, Ryan J. Foley, K. Forster, K. C. Chambers, R. P. Kirshner, Ryan Chornock, James D. Neill, Suvi Gezari, Roger A. Chevalier, W. M. Wood-Vasey, D. C. Martin, S. Rodney, E. A. Magnier, John L. Tonry, R. J. Wainscoat, H. Flewelling, and Nick Kaiser
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Absorption spectroscopy ,FOS: Physical sciences ,Astrophysics ,Magnetar ,01 natural sciences ,Spectral line ,0103 physical sciences ,010306 general physics ,Spectroscopy ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Astronomy and Astrophysics ,Light curve ,Astrophysics - Astrophysics of Galaxies ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Spectral energy distribution ,Astrophysics - High Energy Astrophysical Phenomena ,Radioactive decay ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present the discovery of two ultra-luminous supernovae (SNe) at z ~ 0.9 with the Pan-STARRS1 Medium-Deep Survey. These SNe, PS1-10ky and PS1-10awh, are amongst the most luminous SNe ever discovered, comparable to the unusual transients SN 2005ap and SCP 06F6. Like SN 2005ap and SCP 06F6, they show characteristic high luminosities (M_bol ~ -22.5 mag), blue spectra with a few broad absorption lines, and no evidence for H or He. We have constructed a full multi-color light curve sensitive to the peak of the spectral energy distribution in the rest-frame ultraviolet, and we have obtained time-series spectroscopy for these SNe. Given the similarities between the SNe, we combine their light curves to estimate a total radiated energy over the course of explosion of (0.9-1.4) x 10^51 erg. We find photospheric velocities of 12,000-19,000 km/s with no evidence for deceleration measured across ~3 rest-frame weeks around light-curve peak, consistent with the expansion of an optically-thick massive shell of material. We show that, consistent with findings for other ultra-luminous SNe in this class, radioactive decay is not sufficient to power PS1-10ky, and we discuss two plausible origins for these events: the initial spin-down of a newborn magnetar in a core-collapse SN, or SN shock breakout from the dense circumstellar wind surrounding a Wolf-Rayet star., Comment: Re-Submitted to ApJ
- Published
- 2011
42. PAndromeda - first results from the high-cadence monitoring of M31 with Pan-STARRS 1
- Author
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J. Koppenhoefer, C. Goessl, A. Riffeser, Christopher W. Stubbs, Stella Seitz, E. A. Magnier, R. J. Wainscoat, K. C. Chambers, P. A. Price, John L. Tonry, John Morgan, T. Grav, W. E. Sweeney, Chien-Hsiu Lee, Nick Kaiser, Klaus W. Hodapp, J. N. Heasley, Roberto P. Saglia, Ralf Bender, Ulrich Hopp, Jan Snigula, and W. S. Burgett
- Subjects
Time delay and integration ,Physics ,Cepheid variable ,Milky Way ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Light curve ,Gravitational microlensing ,Astrophysics - Astrophysics of Galaxies ,Stars ,Space and Planetary Science ,Bulge ,Astrophysics of Galaxies (astro-ph.GA) ,Halo - Abstract
The Pan-STARRS 1 (PS1) survey of M31 (PAndromeda) is designed to identify gravitational microlensing events, caused by bulge and disk stars (self-lensing) and by compact matter in the halos of M31 and the Milky Way (halo lensing, or lensing by MACHOs). With the 7 deg2 FOV of PS1, the entire disk of M31 can be imaged with one single pointing. Our aim is to monitor M31 with this wide FOV with daily sampling (20 mins/day). In the 2010 season we acquired in total 91 nights towards M31, with 90 nights in the rP1 and 66 nights in the iP1. The total integration time in rP1 and iP1 are 70740s and 36180s, respectively. As a preliminary analysis, we study a 40'\times40' sub-field in the central region of M31, a 20'\times20' sub-field in the disk of M31 and a 20'\times20' sub-field for the investigation of astrometric precision. We demonstrate that the PSF is good enough to detect microlensing events. We present light curves for 6 candidate microlensing events. This is a competitive rate compared to previous M31 microlensing surveys. We finally also present one example light curve for Cepheids, novae and eclipsing binaries in these sub-fields., 41 pages, 19 figures, 4 tables. Published in AJ
- Published
- 2011
43. TOWARD CHARACTERIZATION OF THE TYPE IIP SUPERNOVA PROGENITOR POPULATION: A STATISTICAL SAMPLE OF LIGHT CURVES FROM Pan-STARRS1
- Author
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Armin Rest, R. P. Kirshner, Christopher M. Waters, R. Lunnan, Edo Berger, Ryan J. Foley, John Morgan, Seppo Mattila, Nick Kaiser, Klaus W. Hodapp, Nathan Edward Sanders, R. P. Kudritzki, W. S. Burgett, Peter W. Draper, Erkki Kankare, Michael Betancourt, M. E. Huber, Gautham Narayan, R. Chornock, Ryan McKinnon, S. J. Smartt, P. Challis, P. A. Price, Dan Milisavljevic, John L. Tonry, Alicia Soderberg, Suvi Gezari, Nigel Metcalfe, Maria R. Drout, G. H. Marion, E. A. Magnier, R. Margutti, and R. J. Wainscoat
- Subjects
Stellar mass ,Astrophysics::High Energy Astrophysical Phenomena ,media_common.quotation_subject ,Population ,general [Supernovae] ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Cosmology ,Luminosity ,Astrophysics::Solar and Stellar Astrophysics ,Red supergiant ,education ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics ,media_common ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,education.field_of_study ,Astronomy and Astrophysics ,Light curve ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,Sky ,Surveys ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
In recent years, wide-field sky surveys providing deep multi-band imaging have presented a new path for indirectly characterizing the progenitor populations of core-collapse supernovae (SN): systematic light curve studies. We assemble a set of 76 grizy-band Type IIP SN light curves from Pan-STARRS1, obtained over a constant survey program of 4 years and classified using both spectroscopy and machine learning-based photometric techniques. We develop and apply a new Bayesian model for the full multi-band evolution of each light curve in the sample. We find no evidence of a sub-population of fast-declining explosions (historically referred to as "Type IIL" SNe). However, we identify a highly significant relation between the plateau phase decay rate and peak luminosity among our SNe IIP. These results argue in favor of a single parameter, likely determined by initial stellar mass, predominantly controlling the explosions of red supergiants. This relation could also be applied for supernova cosmology, offering a standardizable candle good to an intrinsic scatter of 0.2 mag. We compare each light curve to physical models from hydrodynamic simulations to estimate progenitor initial masses and other properties of the Pan-STARRS1 Type IIP SN sample. We show that correction of systematic discrepancies between modeled and observed SN IIP light curve properties and an expanded grid of progenitor properties, are needed to enable robust progenitor inferences from multi-band light curve samples of this kind. This work will serve as a pathfinder for photometric studies of core-collapse SNe to be conducted through future wide field transient searches., Comment: 25 pages plus tables, 19 figures, V2 matches version published in ApJ
- Published
- 2015
44. PROPERTIES OF M31. V. 298 ECLIPSING BINARIES FROM PAndromeda
- Author
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Ralf Bender, Mihael Kodric, Claus Gössl, Chien-Hsiu Lee, Johannes Koppenhoefer, Jan Snigula, A. Riffeser, W. S. Burgett, K. C. Chambers, Klaus-Werner Hodapp, Ulrich Hopp, Nick Kaiser, Rolf-Peter Kudritzki, Stella Seitz, and Christopher Waters
- Subjects
Physics ,FOS: Physical sciences ,Binary number ,Local Group ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Visible radiation ,Light curve ,Galaxy ,Quantitative Biology::Subcellular Processes ,Photometry (optics) ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics::Galaxy Astrophysics - Abstract
The goal of this work is to conduct a photometric study of eclipsing binaries in M31. We apply a modified box-fitting algorithm to search for eclipsing binary candidates and determine their period. We classify these candidates into detached, semi-detached, and contact systems using the Fourier decomposition method. We cross-match the position of our detached candidates with the photometry from Local Group Survey (Massey et al. 2006) and select 13 candidates brighter than 20.5 magnitude in V. The relative physical parameters of these detached candidates are further characterized with Detached Eclipsing Binary Light curve fitter (DEBiL) by Devor (2005). We will followup the detached eclipsing binaries spectroscopically and determine the distance to M31., 19 pages, 7 figures, 1 table, ApJ in press
- Published
- 2014
45. PROPERTIES OF M31. IV. CANDIDATE LUMINOUS BLUE VARIABLES FROM PANDROMEDA
- Author
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H. Flewelling, P. A. Price, Morgan Fraser, A. Riffeser, C. Goessl, Stella Seitz, Ulrich Hopp, Mihael Kodric, Peter W. Draper, Jan Snigula, R. P. Kudritzki, W. S. Burgett, E. A. Magnier, Chien-Hsiu Lee, K. C. Chambers, Nick Kaiser, J. Koppenhoefer, Luciana Bianchi, and R. Bender
- Subjects
Physics ,Spiral galaxy ,010504 meteorology & atmospheric sciences ,massive. [Stars] ,media_common.quotation_subject ,evolution [Stars] ,FOS: Physical sciences ,Local Group ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Galaxy ,Andromeda ,Young age ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,early-type [Stars] ,Space and Planetary Science ,Sky ,individual (M31) [Galaxies] ,0103 physical sciences ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences ,media_common - Abstract
We perform a study on the optical and infrared photometric properties of known luminous blue variables (LBVs) in M31 using the sample of LBV candidates from the Local Group Galaxy Survey (Massey et al. 2007). We find that M31 LBV candidates show photometric variability ranging from 0.375 to 1.576 magnitudes in rP1 during a three year time-span observed by the Pan-STARRS 1 Andromeda survey (PAndromeda). Their near-infrared colors also follow the distribution of Galactic LBVs as shown by Oksala et al. (2013). We use these features as selection criteria to search for unknown LBV candidates in M31. We thus devise a method to search for candidate LBVs using both optical color from the Local Group Galaxy Survey and infrared color from Two Micron All Sky Survey, as well as photometric variations observed by PAndromeda. We find four sources exhibiting common properties of known LBVs. These sources also exhibit UV emission as seen from GALEX, which is one of the previously adopted method to search for LBV candidates. The locations of the LBVs are well aligned withM31 spiral arms as seen in the UV light, suggesting they are evolved stars at young age given their high-mass nature. We compare these candidates with the latest Geneva evolutionary tracks, which show that our new M31 LBV candidates are massive evolved stars with an age of 10 to 100 million years., 30 pages, 13 figures, 3 tables, ApJ in press
- Published
- 2014
46. THE ULTRAVIOLET-BRIGHT, SLOWLY DECLINING TRANSIENT PS1-11af AS A PARTIAL TIDAL DISRUPTION EVENT
- Author
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G. H. Marion, Kathy Roth, Christopher W. Stubbs, Gautham Narayan, K. C. Chambers, S. J. Smartt, D. C. Martin, John L. Tonry, Ryan J. Foley, B. A. Zauderer, H. Flewelling, E. A. Magnier, Ragnhild Lunnan, K. W. Smith, Andy Lawrence, Laura Chomiuk, R. J. Wainscoat, Maria R. Drout, Ian Czekala, Wen-fai Fong, Jason A. Dittmann, Nick Kaiser, Klaus W. Hodapp, M. E. Huber, Alicia Soderberg, Edo Berger, W. S. Burgett, James D. Neill, Suvi Gezari, P. A. Price, Nathan Edward Sanders, Armin Rest, R. Chornock, Daniel Scolnic, Adam G. Riess, Atish Kamble, and R. P. Kirshner
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Astrophysics::High Energy Astrophysical Phenomena ,black hole physics ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Luminosity ,Tidal disruption event ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,accretion, accretion disks ,Photosphere ,Nuclei [galaxies] ,010308 nuclear & particles physics ,Star formation ,Astronomy and Astrophysics ,Light curve ,Redshift ,Supernova ,Space and Planetary Science ,Spectral energy distribution ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present the Pan-STARRS1 discovery of the long-lived and blue transient PS1-11af, which was also detected by GALEX with coordinated observations in the near-ultraviolet (NUV) band. PS1-11af is associated with the nucleus of an early-type galaxy at redshift z=0.4046 that exhibits no evidence for star formation or AGN activity. Four epochs of spectroscopy reveal a pair of transient broad absorption features in the UV on otherwise featureless spectra. Despite the superficial similarity of these features to P-Cygni absorptions of supernovae (SNe), we conclude that PS1-11af is not consistent with the properties of known types of SNe. Blackbody fits to the spectral energy distribution are inconsistent with the cooling, expanding ejecta of a SN, and the velocities of the absorption features are too high to represent material in homologous expansion near a SN photosphere. However, the constant blue colors and slow evolution of the luminosity are similar to previous optically-selected tidal disruption events (TDEs). The shape of the optical light curve is consistent with models for TDEs, but the minimum accreted mass necessary to power the observed luminosity is only ~0.002M_sun, which points to a partial disruption model. A full disruption model predicts higher bolometric luminosities, which would require most of the radiation to be emitted in a separate component at high energies where we lack observations. In addition, the observed temperature is lower than that predicted by pure accretion disk models for TDEs and requires reprocessing to a constant, lower temperature. Three deep non-detections in the radio with the VLA over the first two years after the event set strict limits on the production of any relativistic outflow comparable to Swift J1644+57, even if off-axis., Comment: submitted to ApJ, 22 pages, 14 figures, 4 tables
- Published
- 2013
47. PROPERTIES OF M31. III. CANDIDATE BEAT CEPHEIDS FROM PS1 PANDROMEDA DATA AND THEIR IMPLICATION ON METALLICITY GRADIENT
- Author
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Klaus-Werner Hodapp, Stella Seitz, Paul A. Price, John L. Tonry, H. Flewelling, Johannes Koppenhoefer, Ulrich Hopp, A. Riffeser, Rolf-Peter Kudritzki, Jan Snigula, Mihael Kodric, W. S. Burgett, Chien-Hsiu Lee, Richard J. Wainscoat, Ralf Bender, Claus Gössl, K. C. Chambers, and Nick Kaiser
- Subjects
Physics ,Cepheid variable ,Metallicity ,Overtone ,FOS: Physical sciences ,Beat (acoustics) ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Planetary nebula ,Galaxy ,010309 optics ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
We present a sample of M31 beat Cepheids from the Pan-STARRS 1 PAndromeda campaign. By analyzing three years of PAndromeda data, we identify seventeen beat Cepheids, spreading from a galactocentric distance of 10 to 16 kpc. Since the relation between fundamental mode period and the ratio of fundamental to the first overtone period puts a tight constraint on metallicity we are able to derive the metallicity at the position of the beat Cepheids using the relations from the model of Buchler (2008). Our metallicity estimates show subsolar values within 15 kpc, similar to the metallicities from HII regions (Zurita & Bresolin 2012). We then use the metallicity estimates to calculate the metallicity gradient of the M31 disk, which we find to be closer to the metallicity gradient derived from planetary nebulae (Kwitter et al. 2012) than the metallicity gradient from HII regions (Zurita & Bresolin 2012)., 32 pages, 7 figures, 3 tables
- Published
- 2013
48. THE PAN-STARRS 1 PHOTOMETRIC REFERENCE LADDER, RELEASE 12.01
- Author
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John L. Tonry, H. Flewelling, P. A. Price, John Morgan, D. P. Finkbeiner, Nick Kaiser, Christopher W. Stubbs, W. E. Sweeney, Edward F. Schlafly, Mario Juric, E. A. Magnier, R. P. Kudritzki, W. S. Burgett, and K. C. Chambers
- Subjects
Physics ,010308 nuclear & particles physics ,media_common.quotation_subject ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Declination ,Square degree ,Photometry (optics) ,Stars ,Space and Planetary Science ,Sky ,Area coverage ,0103 physical sciences ,Saturation (graph theory) ,010303 astronomy & astrophysics ,Data release ,media_common - Abstract
As of 2012 Jan 21, the Pan-STARRS 1 3\pi Survey has observed the 3/4 of the sky visible from Hawaii with a minimum of 2 and mean of 7.6 observations in 5 filters, g_p1, r_p1, i_p1, z_p1, y_p1. Now at the end of the second year of the mission, we are in a position to make an initial public release of a portion of this unprecedented dataset. This article describes the PS1 Photometric Ladder, Release 12.01 This is the first of a series of data releases to be generated as the survey coverage increases and the data analysis improves. The Photometric Ladder has rungs every hour in RA and at 4 intervals in declination. We will release updates with increased area coverage (more rungs) from the latest dataset until the PS1 survey and the final re-reduction are completed. The currently released catalog presents photometry of \approx 1000 objects per square degree in the rungs of the ladder. Saturation occurs at g_p1, r_p1, i_p1 \approx 13.5; z_p1 \approx 13.0; and y_p1 \approx 12.0. Photometry is provided for stars down to g_p1, r_p1, i_p1 \approx 19.1 in the AB system. This data release depends on the rigid `Ubercal' photometric calibration using only the photometric nights, with systematic uncertainties of (8.0, 7.0, 9.0, 10.7, 12.4) millimags in (g_p1, r_p1, i_p1, z_p1, y_p1). Areas covered only with lower quality nights are also included, and have been tied to the Ubercal solution via relative photometry; photometric accuracy of the non-photometric regions is lower and should be used with caution.
- Published
- 2013
49. THEGALEXTIME DOMAIN SURVEY. I. SELECTION AND CLASSIFICATION OF OVER A THOUSAND ULTRAVIOLET VARIABLE SOURCES
- Author
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K. Forster, M. E. Huber, James D. Neill, Patrick Morrissey, Suvi Gezari, Ted K. Wyder, David Schiminovich, Luciana Bianchi, Nick Kaiser, D. C. Martin, Susan G. Neff, K. C. Chambers, W. S. Burgett, John L. Tonry, Timothy M. Heckman, P. A. Price, E. A. Magnier, and Mark Seibert
- Subjects
Physics ,Supermassive black hole ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,RR Lyrae variable ,Light curve ,Stars ,Supernova ,Space and Planetary Science ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Variable star ,Astrophysics::Galaxy Astrophysics - Abstract
We present the selection and classification of over a thousand ultraviolet (UV) variable sources discovered in ~ 40 deg^2 of GALEX Time Domain Survey (TDS) NUV images observed with a cadence of 2 days and a baseline of observations of ~ 3 years. The GALEX TDS fields were designed to be in spatial and temporal coordination with the Pan-STARRS1 Medium Deep Survey, which provides deep optical imaging and simultaneous optical transient detections via image differencing. We characterize the GALEX photometric errors empirically as a function of mean magnitude, and select sources that vary at the 5\sigma level in at least one epoch. We measure the statistical properties of the UV variability, including the structure function on timescales of days and years. We report classifications for the GALEX TDS sample using a combination of optical host colors and morphology, UV light curve characteristics, and matches to archival X-ray, and spectroscopy catalogs. We classify 62% of the sources as active galaxies (358 quasars and 305 active galactic nuclei), and 10% as variable stars (including 37 RR Lyrae, 53 M dwarf flare stars, and 2 cataclysmic variables). The remaining unclassified sources include UV-bright extragalactic transients, two of which have been spectroscopically confirmed to be a young core-collapse supernova and a flare from the tidal disruption of a star by dormant supermassive black hole. We calculate a surface density for variable sources in the UV with NUV 0.2 mag of ~ 8.0, 7.7, and 1.8 deg^-2 for quasars, AGNs, and RR Lyrae stars, respectively. We also calculate a surface density rate in the UV for transient sources, using the effective survey time at the cadence appropriate to each class, of ~ 15 and 52 deg^-2 yr^-1 for M dwarfs and extragalactic transients, respectively. (Abridged.)
- Published
- 2013
50. DISPLAYING THE HETEROGENEITY OF THE SN 2002cx-LIKE SUBCLASS OF TYPE Ia SUPERNOVAE WITH OBSERVATIONS OF THE Pan-STARRS-1 DISCOVERED SN 2009ku
- Author
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G. Narayan, R. J. Foley, E. Berger, M. T. Botticella, R. Chornock, M. E. Huber, A. Rest, D. Scolnic, S. Smartt, S. Valenti, A. M. Soderberg, W. S. Burgett, K. C. Chambers, H. A. Flewelling, G. Gates, T. Grav, N. Kaiser, R. P. Kirshner, E. A. Magnier, J. S. Morgan, P. A. Price, A. G. Riess, C. W. Stubbs, W. E. Sweeney, J. L. Tonry, R. J. Wainscoat, C. Waters, and W. M. Wood-Vasey
- Subjects
Physics ,education.field_of_study ,Brightness ,Population ,FOS: Physical sciences ,Astronomy and Astrophysics ,Class (philosophy) ,Astrophysics ,Type (model theory) ,Light curve ,01 natural sciences ,Luminosity ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,10. No inequality ,010306 general physics ,Ejecta ,education ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
SN2009ku, discovered by Pan-STARRS-1, is a Type Ia supernova (SNIa), and a member of the distinct SN2002cx-like class of SNeIa. Its light curves are similar to the prototypical SN2002cx, but are slightly broader and have a later rise to maximum in g. SN2009ku is brighter (~0.6 mag) than other SN2002cx-like objects, peaking at M_V = -18.4 mag - which is still significantly fainter than typical SNeIa. SN2009ku, which had an ejecta velocity of ~2000 kms^-1 at 18 days after maximum brightness is spectroscopically most similar to SN2008ha, which also had extremely low-velocity ejecta. However, SN2008ha had an exceedingly low luminosity, peaking at M_V = -14.2 mag, ~4 mag fainter than SN2009ku. The contrast of high luminosity and low ejecta velocity for SN2009ku is contrary to an emerging trend seen for the SN2002cx class. SN2009ku is a counter-example of a previously held belief that the class was more homogeneous than typical SNeIa, indicating that the class has a diverse progenitor population and/or complicated explosion physics. As the first example of a member of this class of objects from the new generation of transient surveys, SN2009ku is an indication of the potential for these surveys to find rare and interesting objects., Comment: 7 pages, 3 figures
- Published
- 2011
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