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Your search keyword '"Angus, C. R."' showing total 6 results
Start Over Author "Angus, C. R." Publisher stockholms universitet, oskar klein-centrum for kosmopartikelfysik (okc)
6 results on '"Angus, C. R."'

1. SN 2023emq : A Flash-ionized Ibn Supernova with Possible C iii Emission

Author

Pursiainen, M., Leloudas, G., Schulze, Steve, Charalampopoulos, P., Angus, C. R., Anderson, J. P., Bauer, F., Chen, T.-W., Galbany, L., Gromadzki, M., Gutiérrez, C. P., Inserra, C., Lyman, J., Müller-Bravo, T. E., Nicholl, M., Smartt, S. J., Tartaglia, L., Wiseman, P., Young, D. R., Pursiainen, M., Leloudas, G., Schulze, Steve, Charalampopoulos, P., Angus, C. R., Anderson, J. P., Bauer, F., Chen, T.-W., Galbany, L., Gromadzki, M., Gutiérrez, C. P., Inserra, C., Lyman, J., Müller-Bravo, T. E., Nicholl, M., Smartt, S. J., Tartaglia, L., Wiseman, P., and Young, D. R.

Abstract

SN 2023emq is a fast-evolving transient initially classified as a rare Type Icn supernova (SN), interacting with a H- and He-free circumstellar medium (CSM) around maximum light. Subsequent spectroscopy revealed the unambiguous emergence of narrow He lines, confidently placing SN 2023emq in the more common Type Ibn class. Photometrically, SN 2023emq has several uncommon properties regardless of its class, including its extreme initial decay (faster than >90% of Type Ibn/Icn SNe) and sharp transition in the decline rate from 0.20 to 0.07 mag day−1 at +20 days. The bolometric light curve can be modeled as CSM interaction with 0.32M⊙ of ejecta and 0.12M⊙ of CSM, with 0.006M⊙ of nickel, as expected of fast, interacting SNe. Furthermore, broadband polarimetry at +8.7 days (P = 0.55% ± 0.30%) is consistent with spherical symmetry. A discovery of a transitional Type Icn/Ibn SN would be unprecedented and would give valuable insights into the nature of mass loss suffered by the progenitor just before death, but we favor an interpretation that SN 2023emq is a Type Ibn SN that exhibited flash-ionized features in the earliest spectrum, as the features are not an exact match with other Type Icn SNe to date. However, the feature at 5700 Å, in the region of C iii and N ii emission, is significantly stronger in SN 2023emq than in the few other flash-ionized Type Ibn SNe, and if it is related to C iii, it possibly implies a continuum of properties between the two classes.

Published
2023
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2. Hubble constant and nuclear equation of state from kilonova spectro-photometric light curves

Author

Pérez-García, M. A., Izzo, L., Barba-González, D., Bulla, Mattia, Sagués-Carracedo, Ana, Pérez, E., Albertus, C., Dhawan, S., Prada, F., Agnello, A., Angus, C. R., Bruun, S. H., del Burgo, C., Dominguez-Tagle, C., Gall, C., Goobar, Ariel, Hjorth, J., Jones, D., López-Sánchez, A. R., Sollerman, Jesper, Pérez-García, M. A., Izzo, L., Barba-González, D., Bulla, Mattia, Sagués-Carracedo, Ana, Pérez, E., Albertus, C., Dhawan, S., Prada, F., Agnello, A., Angus, C. R., Bruun, S. H., del Burgo, C., Dominguez-Tagle, C., Gall, C., Goobar, Ariel, Hjorth, J., Jones, D., López-Sánchez, A. R., and Sollerman, Jesper

Abstract

The merger of two compact objects of which at least one is a neutron star is signalled by transient electromagnetic emission in a kilonova (KN). This event is accompanied by gravitational waves and possibly other radiation messengers such as neutrinos or cosmic rays. The electromagnetic emission arises from the radioactive decay of heavy r-process elements synthesized in the material ejected during and after the merger. In this paper we show that the analysis of KNe light curves can provide cosmological distance measurements and constrain the properties of the ejecta. In this respect, MAAT, the new Integral Field Unit in the OSIRIS spectrograph on the 10.4 m Gran Telescopio CANARIAS (GTC), is well suited for the study of KNe by performing absolute spectro-photometry over the entire 3600 − 10 000 Å spectral range. Here, we study the most representative cases regarding the scientific interest of KNe from binary neutron stars, and we evaluate the observational prospects and performance of MAAT on the GTC to do the following: (a) study the impact of the equation of state on the KN light curve, and determine to what extent bounds on neutron star (NS) radii or compactness deriving from KN peak magnitudes can be identified and (b) measure the Hubble constant, H0, with precision improved by up to 40%, when both gravitational wave data and photometric-light curves are used. In this context we discuss how the equation of state, the viewing angle, and the distance affect the precision and estimated value of H0.

Published
2022
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3. DES16C3cje : A low-luminosity, long-lived supernova

Author

Gutierrez, C. P., Sullivan, M., Martinez, L., Bersten, M. C., Inserra, C., Smith, M., Anderson, J. P., Pan, Y.-C., Pastorello, A., Galbany, L., Nugent, P., Angus, C. R., Barbarino, Cristina, Carollo, D., Chen, T.-W., Davis, T. M., Della Valle, M., Foley, R. J., Fraser, M., Frohmaier, C., Gonzalez-Gaitan, S., Gromadzki, M., Kankare, E., Kokotanekova, R., Kollmeier, J., Lewis, G. F., Magee, M. R., Maguire, K., Moller, A., Morrell, N., Nicholl, M., Pursiainen, M., Sollerman, Jesper, Sommer, N. E., Swann, E., Tucker, B. E., Wiseman, P., Aguena, M., Allam, S., Avila, S., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Costanzi, M., da Costa, L. N., De Vicente, J., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hinton, S. R., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Menanteau, F., Miquel, R., Morganson, E., Palmese, A., Paz-Chinchon, F., Plazas, A. A., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Serrano, S., Sevilla-Noarbe, I., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Varga, T. N., Walker, A. R., Wilkinson, R., Gutierrez, C. P., Sullivan, M., Martinez, L., Bersten, M. C., Inserra, C., Smith, M., Anderson, J. P., Pan, Y.-C., Pastorello, A., Galbany, L., Nugent, P., Angus, C. R., Barbarino, Cristina, Carollo, D., Chen, T.-W., Davis, T. M., Della Valle, M., Foley, R. J., Fraser, M., Frohmaier, C., Gonzalez-Gaitan, S., Gromadzki, M., Kankare, E., Kokotanekova, R., Kollmeier, J., Lewis, G. F., Magee, M. R., Maguire, K., Moller, A., Morrell, N., Nicholl, M., Pursiainen, M., Sollerman, Jesper, Sommer, N. E., Swann, E., Tucker, B. E., Wiseman, P., Aguena, M., Allam, S., Avila, S., Bertin, E., Brooks, D., Buckley-Geer, E., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Costanzi, M., da Costa, L. N., De Vicente, J., Desai, S., Diehl, H. T., Doel, P., Eifler, T. F., Flaugher, B., Fosalba, P., Frieman, J., Garcia-Bellido, J., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hinton, S. R., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Menanteau, F., Miquel, R., Morganson, E., Palmese, A., Paz-Chinchon, F., Plazas, A. A., Sako, M., Sanchez, E., Scarpine, V., Schubnell, M., Serrano, S., Sevilla-Noarbe, I., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., Varga, T. N., Walker, A. R., and Wilkinson, R.

Abstract

We present DES16C3cje, a low-luminosity, long-lived type II supernova (SN II) at redshift 0.0618, detected by the Dark Energy Survey (DES). DES16C3cje is a unique SN. The spectra are characterized by extremely narrow photospheric lines corresponding to very low expansion velocities of less than or similar to 1500 km s(-1), and the light curve shows an initial peak that fades after 50 d before slowly rebrightening over a further 100 d to reach an absolute brightness of M-r similar to 15.5 mag. The decline rate of the late-time light curve is then slower than that expected from the powering by radioactive decay of Co-56, but is comparable to that expected from accretion power. Comparing the bolometric light curve with hydrodynamical models, we find that DES16C3cje can be explained by either (i) a low explosion energy (0.11 foe) and relatively large Ni-56 production of 0.075 M-circle dot from an similar to 15 M-circle dot red supergiant progenitor typical of other SNe II, or (ii) a relatively compact similar to 40 M-circle dot star, explosion energy of 1 foe, and 0.08 M-circle dot of Ni-56. Both scenarios require additional energy input to explain the late-time light curve, which is consistent with fallback accretion at a rate of similar to 0.5 x 10(-)(8) M-circle dot s(-1).

Published
2020
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4. Discovery and follow-up of the unusual nuclear transient OGLE17aaj

Author

Gromadzki, M., Hamanowicz, A., Wyrzykowski, L., Sokolovsky, K. V., Fraser, M., Kozłowski, Sz., Guillochon, J., Arcavi, I., Trakhtenbrot, B., Jonker, P. G., Mattila, S., Udalski, A., Szymański, M. K., Soszyński, I., Poleski, R., Pietrukowicz, P., Skowron, J., Mróz, P., Ulaczyk, K., Pawlak, M., Rybicki, K. A., Sollerman, Jesper, Taddia, Francesco, Kostrzewa-Rutkowska, Z., Onori, F., Young, D. R., Maguire, K., Smartt, S. J., Inserra, C., Gal-Yam, A., Rau, A., Chen, T. -W., Angus, C. R., Buckley, D. A. H., Gromadzki, M., Hamanowicz, A., Wyrzykowski, L., Sokolovsky, K. V., Fraser, M., Kozłowski, Sz., Guillochon, J., Arcavi, I., Trakhtenbrot, B., Jonker, P. G., Mattila, S., Udalski, A., Szymański, M. K., Soszyński, I., Poleski, R., Pietrukowicz, P., Skowron, J., Mróz, P., Ulaczyk, K., Pawlak, M., Rybicki, K. A., Sollerman, Jesper, Taddia, Francesco, Kostrzewa-Rutkowska, Z., Onori, F., Young, D. R., Maguire, K., Smartt, S. J., Inserra, C., Gal-Yam, A., Rau, A., Chen, T. -W., Angus, C. R., and Buckley, D. A. H.

Abstract

Aims. We report on the discovery and follow-up of a peculiar transient, OGLE17aaj, which occurred in the nucleus of a weakly active galaxy. We investigate whether it can be interpreted as a new candidate for a tidal disruption event (TDE). Methods. We present the OGLE-IV light curve that covers the slow 60-day-long rise to maximum along with photometric, spectro-scopic, and X-ray follow-up during the first year. Results. OGLE17aaj is a nuclear transient exhibiting some properties similar to previously found TDEs, including a long rise time, lack of colour-temperature evolution, and high black-body temperature. On the other hand, its narrow emission lines and slow post-peak evolution are different from previously observed TDEs. Its spectrum and light-curve evolution is similar to F01004-2237 and AT 2017bgt. Signatures of historical low-level nuclear variability suggest that OGLE17aaj may instead be related to a new type of accretion event in active super-massive black holes.

Published
2019
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5. A nearby super-luminous supernova with a long pre-maximum plateau and strong C (II) features

Author

Anderson, J. P., Pessi, P. J., Dessart, L., Inserra, C., Hiramatsu, D., Taggart, K., Smartt, S. J., Leloudas, G., Chen, T.-W., Möller, A., Roy, R., Schulze, S., Perley, D., Selsing, J., Prentice, S. J., Gal-Yam, A., Angus, C. R., Arcavi, I., Ashall, C., Bulla, Mattia, Bray, C., Burke, J., Callis, E., Cartier, R., Chang, S.-W., Chambers, K., Clark, P., Denneau, L., Dennefeld, M., Flewelling, H., Fraser, M., Galbany, L., Gromadzki, M., Gutiérrez, C. P., Heinze, A., Hosseinzadeh, G., Howell, D. A., Hsiao, E. Y., Kankare, E., Kostrzewa-Rutkowska, Z., Magnier, E., Maguire, K., Mazzali, P., McBrien, O., McCully, C., Morrell, N., Lowe, T. B., Onken, C. A., Onori, F., Phillips, M. M., Rest, A., Ridden-Harper, R., Ruiter, A. J., Sand, D. J., Smith, K. W., Smith, M., Stalder, B., Stritzinger, M. D., Sullivan, M., Tonry, J. L., Tucker, B. E., Valenti, S., Wainscoat, R., Waters, C. Z., Wolf, C., Young, D., Anderson, J. P., Pessi, P. J., Dessart, L., Inserra, C., Hiramatsu, D., Taggart, K., Smartt, S. J., Leloudas, G., Chen, T.-W., Möller, A., Roy, R., Schulze, S., Perley, D., Selsing, J., Prentice, S. J., Gal-Yam, A., Angus, C. R., Arcavi, I., Ashall, C., Bulla, Mattia, Bray, C., Burke, J., Callis, E., Cartier, R., Chang, S.-W., Chambers, K., Clark, P., Denneau, L., Dennefeld, M., Flewelling, H., Fraser, M., Galbany, L., Gromadzki, M., Gutiérrez, C. P., Heinze, A., Hosseinzadeh, G., Howell, D. A., Hsiao, E. Y., Kankare, E., Kostrzewa-Rutkowska, Z., Magnier, E., Maguire, K., Mazzali, P., McBrien, O., McCully, C., Morrell, N., Lowe, T. B., Onken, C. A., Onori, F., Phillips, M. M., Rest, A., Ridden-Harper, R., Ruiter, A. J., Sand, D. J., Smith, K. W., Smith, M., Stalder, B., Stritzinger, M. D., Sullivan, M., Tonry, J. L., Tucker, B. E., Valenti, S., Wainscoat, R., Waters, C. Z., Wolf, C., and Young, D.

Abstract

Context. Super-luminous supernovae (SLSNe) are rare events defined as being significantly more luminous than normal terminal stellar explosions. The source of the additional power needed to achieve such luminosities is still unclear. Discoveries in the local Universe (i.e. z < 0.1) are scarce, but afford dense multi-wavelength observations. Additional low-redshift objects are therefore extremely valuable. Aims. We present early-time observations of the type I SLSN ASASSN-18km/SN 2018bsz. These data are used to characterise the event and compare to literature SLSNe and spectral models. Host galaxy properties are also analysed. Methods. Optical and near-IR photometry and spectroscopy were analysed. Early-time ATLAS photometry was used to constrain the rising light curve. We identified a number of spectral features in optical-wavelength spectra and track their time evolution. Finally, we used archival host galaxy photometry together with H( II )region spectra to constrain the host environment. Results. ASASSN-18km/SN 2018bsz is found to be a type I SLSN in a galaxy at a redshift of 0.0267 (111 Mpc), making it the lowest-redshift event discovered to date. Strong C- II lines are identified in the spectra. Spectral models produced by exploding a Wolf-Rayet progenitor and injecting a magnetar power source are shown to be qualitatively similar to ASASSN-18km/SN 2018bsz, contrary to most SLSNe-I that display weak or non-existent C (II) lines. ASASSN-18km/SN 2018bsz displays along, slowly rising, red plateau of >26 days, before a steeper, faster rise to maximum. The host has an absolute magnitude of -19.8 mag (r), a mass of M-* = 1.5(-0.33)(+0.08) x 10(9) M-circle dot, and a star formation rate of =0.50(-0.19)(+2.22) M-circle dot yr(-1). A nearby H (II) region has an oxygen abundance (O3N2) of 8.31 +/- 0.01 dex.

Published
2018
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6. A kilonova as the electromagnetic counterpart to a gravitational-wave source

Author

Smartt, S. J., Chen, T. -W., Jerkstrand, A., Coughlin, M., Kankare, E., Sim, S. A., Fraser, M., Inserra, C., Maguire, K., Chambers, K. C., Huber, M. E., Kruhler, T., Leloudas, G., Magee, M., Shingles, L. J., Smith, K. W., Young, D. R., Tonry, J., Kotak, R., Gal-Yam, A., Lyman, J. D., Homan, D. S., Agliozzo, C., Anderson, J. P., Angus, C. R., Ashall, C., Barbarino, Cristina, Bauer, F. E., Berton, M., Botticella, M. T., Bulla, Mattia, Bulger, J., Cannizzaro, G., Cano, Z., Cartier, R., Cikota, A., Clark, P., De Cia, A., Della Valle, M., Denneau, L., Dennefeld, M., Dessart, L., Dimitriadis, G., Elias-Rosa, N., Firth, R. E., Flewelling, H., Floers, A., Franckowiak, A., Frohmaier, C., Galbany, L., Gonzalez-Gaitan, S., Greiner, J., Gromadzki, M., Guelbenzu, A. Nicuesa, Gutierrez, C. P., Hamanowicz, A., Hanlon, L., Harmanen, J., Heintz, K. E., Heinze, A., Hernandez, M. -S., Hodgkin, S. T., Hook, I. M., Izzo, L., James, P. A., Jonker, P. G., Kerzendorf, W. E., Klose, S., Kostrzewa-Rutkowska, Z., Kowalski, M., Kromer, M., Kuncarayakti, H., Lawrence, A., Lowe, T. B., Magnier, E. A., Manulis, I., Martin-Carrillo, A., Mattila, S., McBrien, O., Mueller, A., Nordin, J., O'Neill, D., Onori, F., Palmerio, J. T., Pastorello, A., Patat, F., Pignata, G., Podsiadlowski, Ph., Pumo, M. L., Prentice, S. J., Rau, A., Razza, A., Rest, A., Reynolds, T., Roy, Rupak, Ruiter, A. J., Rybicki, K. A., Salmon, L., Schady, P., Schultz, A. S. B., Schweyer, T., Seitenzahl, I. R., Smith, M., Sollerman, Jesper, Stalder, B., Stubbs, C. W., Sullivan, M., Szegedi, H., Taddia, Francesco, Taubenberger, S., Terreran, G., van Soelen, B., Vos, J., Wainscoat, R. J., Walton, N. A., Waters, C., Weiland, H., Willman, M., Wiseman, P., Wright, D. E., Wyrzykowski, L., Yaron, O., Smartt, S. J., Chen, T. -W., Jerkstrand, A., Coughlin, M., Kankare, E., Sim, S. A., Fraser, M., Inserra, C., Maguire, K., Chambers, K. C., Huber, M. E., Kruhler, T., Leloudas, G., Magee, M., Shingles, L. J., Smith, K. W., Young, D. R., Tonry, J., Kotak, R., Gal-Yam, A., Lyman, J. D., Homan, D. S., Agliozzo, C., Anderson, J. P., Angus, C. R., Ashall, C., Barbarino, Cristina, Bauer, F. E., Berton, M., Botticella, M. T., Bulla, Mattia, Bulger, J., Cannizzaro, G., Cano, Z., Cartier, R., Cikota, A., Clark, P., De Cia, A., Della Valle, M., Denneau, L., Dennefeld, M., Dessart, L., Dimitriadis, G., Elias-Rosa, N., Firth, R. E., Flewelling, H., Floers, A., Franckowiak, A., Frohmaier, C., Galbany, L., Gonzalez-Gaitan, S., Greiner, J., Gromadzki, M., Guelbenzu, A. Nicuesa, Gutierrez, C. P., Hamanowicz, A., Hanlon, L., Harmanen, J., Heintz, K. E., Heinze, A., Hernandez, M. -S., Hodgkin, S. T., Hook, I. M., Izzo, L., James, P. A., Jonker, P. G., Kerzendorf, W. E., Klose, S., Kostrzewa-Rutkowska, Z., Kowalski, M., Kromer, M., Kuncarayakti, H., Lawrence, A., Lowe, T. B., Magnier, E. A., Manulis, I., Martin-Carrillo, A., Mattila, S., McBrien, O., Mueller, A., Nordin, J., O'Neill, D., Onori, F., Palmerio, J. T., Pastorello, A., Patat, F., Pignata, G., Podsiadlowski, Ph., Pumo, M. L., Prentice, S. J., Rau, A., Razza, A., Rest, A., Reynolds, T., Roy, Rupak, Ruiter, A. J., Rybicki, K. A., Salmon, L., Schady, P., Schultz, A. S. B., Schweyer, T., Seitenzahl, I. R., Smith, M., Sollerman, Jesper, Stalder, B., Stubbs, C. W., Sullivan, M., Szegedi, H., Taddia, Francesco, Taubenberger, S., Terreran, G., van Soelen, B., Vos, J., Wainscoat, R. J., Walton, N. A., Waters, C., Weiland, H., Willman, M., Wiseman, P., Wright, D. E., Wyrzykowski, L., and Yaron, O.

Abstract

Gravitational waves were discovered with the detection of binary black-hole mergers(1) and they should also be detectable from lower-mass neutron-star mergers. These are predicted to eject material rich in heavy radioactive isotopes that can power an electromagnetic signal. This signal is luminous at optical and infrared wavelengths and is called a kilonova(2-5). The gravitational-wave source GW170817 arose from a binary neutron-star merger in the nearby Universe with a relatively well confined sky position and distance estimate(6). Here we report observations and physical modelling of a rapidly fading electromagnetic transient in the galaxy NGC 4993, which is spatially coincident with GW170817 and with a weak, short.-ray burst(7,8). The transient has physical parameters that broadly match the theoretical predictions of blue kilonovae from neutron-star mergers. The emitted electromagnetic radiation can be explained with an ejected mass of 0.04 +/- 0.01 solar masses, with an opacity of less than 0.5 square centimetres per gram, at a velocity of 0.2 +/- 0.1 times light speed. The power source is constrained to have a power-law slope of -1.2 +/- 0.3, consistent with radioactive powering from r-process nuclides. (The r-process is a series of neutron capture reactions that synthesise many of the elements heavier than iron.) We identify line features in the spectra that are consistent with light r-process elements (atomic masses of 90-140). As it fades, the transient rapidly becomes red, and a higher-opacity, lanthanide-rich ejecta component may contribute to the emission. This indicates that neutron-star mergers produce gravitational waves and radioactively powered kilonovae, and are a nucleosynthetic source of the r-process elements.

Published
2017
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