Browsing by Author "Rest, Armin"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- ItemDeep drilling in the time domain with DECam: survey characterization(2023) Graham, Melissa L.; Knop, Robert A.; Kennedy, Thomas D.; Nugent, Peter E.; Bellm, Eric; Catelan, Márcio; Patel, Avi; Smotherman, Hayden; Soraisam, Monika; Stetzler, Steven; Aldoroty, Lauren N.; Awbrey, Autumn; Baeza-Villagra, Karina; Bernardinelli, Pedro H.; Federica Bianco, Federica; Brout, Dillon; Clarke, Riley; Clarkson, William I.; Collett, Thomas; Davenport, James R.; Fu, Shenming; Gizis, John E.; Heinze, Ari; Hu, Lei; Jha, Saurabh W.; Jurić, Mario; Kalmbach, J. Bryce; Kim, Alex; Lee, Chien-Hsiu; Lidman, Chris; Magee, Mark; Martínez-Vázquez, Clara E.; Matheson, Thomas; Narayan, Gautham; Palmese, Antonella; Phillips, Christopher A.; Rabus, Markus; Rest, Armin; Rodríguez-Segovia, Nicolás; Street, Rachel; Vivas, A. Katherina; Wang, Lifan; Wolf, Nicholas; Yang, Jiawen
- ItemGround-based and JWST Observations of SN 2022pul. I. Unusual Signatures of Carbon, Oxygen, and Circumstellar Interaction in a Peculiar Type Ia Supernova(2024) Siebert, Matthew R.; Kwok, Lindsey A.; Johansson, Joel; Jha, Saurabh W.; Blondin, Stephane; Dessart, Luc; Foley, Ryan J.; Hillier, D. John; Larison, Conor; Pakmor, Ruediger; Temim, Tea; Andrews, Jennifer E.; Auchettl, Katie; Badenes, Carles; Barna, Barnabas; Bostroem, K. Azalee; Brenner Newman, Max J.; Brink, Thomas G.; Bustamante-Rosell, Maria Jose; Camacho-Neves, Yssavo; Clocchiatti, Alejandro; Coulter, David A.; Davis, Kyle W.; Deckers, Maxime; Dimitriadis, Georgios; Dong, Yize; Farah, Joseph; Filippenko, Alexei V.; Floers, Andreas; Fox, Ori D.; Garnavich, Peter; Gonzalez, Estefania Padilla; Graur, Or; Hambsch, Franz-Josef; Hosseinzadeh, Griffin; Howell, D. Andrew; Hughes, John P.; Kerzendorf, Wolfgang E.; Le Saux, Xavier K.; Maeda, Keiichi; Maguire, Kate; McCully, Curtis; Mihalenko, Cassidy; Newsome, Megan; O'Brien, John T.; Pearson, Jeniveve; Pellegrino, Craig; Pierel, Justin D. R.; Polin, Abigail; Rest, Armin; Rojas-Bravo, Cesar; Sand, David J.; Schwab, Michaela; Shahbandeh, Melissa; Shrestha, Manisha; Smith, Nathan; Strolger, Louis-Gregory; Szalai, Tamas; Taggart, Kirsty; Terreran, Giacomo; Terwel, Jacco H.; Tinyanont, Samaporn; Valenti, Stefano; Vinko, Jozsef; Wheeler, J. Craig; Yang, Yi; Zheng, Weikang; Ashall, Chris; DerKacy, James M.; Galbany, Lluis; Hoeflich, Peter; Hsiao, Eric; de Jaeger, Thomas; Lu, Jing; Maund, Justyn; Medler, Kyle; Morrell, Nidia; Shappee, Benjamin J.; Stritzinger, Maximilian; Suntzeff, Nicholas; Tucker, Michael; Wang, LifanNebular-phase observations of peculiar Type Ia supernovae (SNe Ia) provide important constraints on progenitor scenarios and explosion dynamics for both these rare SNe and the more common, cosmologically useful SNe Ia. We present observations from an extensive ground- and space-based follow-up campaign to characterize SN 2022pul, a super-Chandrasekhar mass SN Ia (alternatively "03fg-like" SN), from before peak brightness to well into the nebular phase across optical to mid-infrared (MIR) wavelengths. The early rise of the light curve is atypical, exhibiting two distinct components, consistent with SN Ia ejecta interacting with dense carbon-oxygen (C/O)-rich circumstellar material (CSM). In the optical, SN 2022pul is most similar to SN 2012dn, having a low estimated peak luminosity (M B = -18.9 mag) and high photospheric velocity relative to other 03fg-like SNe. In the nebular phase, SN 2022pul adds to the increasing diversity of the 03fg-like subclass. From 168 to 336 days after peak B-band brightness, SN 2022pul exhibits asymmetric and narrow emission from [O i] lambda lambda 6300, 6364 (FWHM approximate to 2000 km s-1), strong, broad emission from [Ca ii] lambda lambda 7291, 7323 (FWHM approximate to 7300 km s-1), and a rapid Fe iii to Fe ii ionization change. Finally, we present the first ever optical-to-MIR nebular spectrum of an 03fg-like SN Ia using data from JWST. In the MIR, strong lines of neon and argon, weak emission from stable nickel, and strong thermal dust emission (with T approximate to 500 K), combined with prominent [O i] in the optical, suggest that SN 2022pul was produced by a white dwarf merger within C/O-rich CSM.
- ItemGround-based and JWST Observations of SN 2022pul. II. Evidence from Nebular Spectroscopy for a Violent Merger in a Peculiar Type Ia Supernova(2024) Kwok, Lindsey A.; Siebert, Matthew R.; Johansson, Joel; Jha, Saurabh W.; Blondin, Stephane; Dessart, Luc; Foley, Ryan J.; Hillier, D. John; Larison, Conor; Pakmor, Ruediger; Temim, Tea; Andrews, Jennifer E.; Auchettl, Katie; Badenes, Carles; Barnabas, Barna; Bostroem, K. Azalee; Brenner Newman, Max J.; Brink, Thomas G.; Bustamante-Rosell, Maria Jose; Camacho-Neves, Yssavo; Clocchiatti, Alejandro; Coulter, David A.; Davis, Kyle W.; Deckers, Maxime; Dimitriadis, Georgios; Dong, Yize; Farah, Joseph; Filippenko, Alexei V.; Floers, Andreas; Fox, Ori D.; Garnavich, Peter; Padilla Gonzalez, Estefania; Graur, Or; Hambsch, Franz-Josef; Hosseinzadeh, Griffin; Howell, D. Andrew; Hughes, John P.; Kerzendorf, Wolfgang E.; Saux, Xavier K.; Maeda, Keiichi; Maguire, Kate; McCully, Curtis; Mihalenko, Cassidy; Newsome, Megan; O'Brien, John T.; Pearson, Jeniveve; Pellegrino, Craig; Pierel, Justin D. R.; Polin, Abigail; Rest, Armin; Rojas-Bravo, Cesar; Sand, David J.; Schwab, Michaela; Shahbandeh, Melissa; Shrestha, Manisha; Smith, Nathan; Strolger, Louis-Gregory; Szalai, Tamas; Taggart, Kirsty; Terreran, Giacomo; Terwel, Jacco H.; Tinyanont, Samaporn; Valenti, Stefano; Vinko, Jozsef; Wheeler, J. Craig; Yang, Yi; Zheng, WeiKang; Ashall, Chris; DerKacy, James M.; Galbany, Lluis; Hoeflich, Peter; de Jaeger, Thomas; Lu, Jing; Maund, Justyn; Medler, Kyle; Morell, Nidia; Shappee, Benjamin J.; Stritzinger, Maximilian; Suntzeff, Nicholas; Tucker, Michael; Wang, LifanWe present an analysis of ground-based and JWST observations of SN 2022pul, a peculiar "03fg-like" (or "super-Chandrasekhar") Type Ia supernova (SN Ia), in the nebular phase at 338 days postexplosion. Our combined spectrum continuously covers 0.4-14 mu m and includes the first mid-infrared spectrum of a 03fg-like SN Ia. Compared to normal SN Ia 2021aefx, SN 2022pul exhibits a lower mean ionization state, asymmetric emission-line profiles, stronger emission from the intermediate-mass elements (IMEs) argon and calcium, weaker emission from iron-group elements (IGEs), and the first unambiguous detection of neon in a SN Ia. A strong, broad, centrally peaked [Ne ii] line at 12.81 mu m was previously predicted as a hallmark of "violent merger" SN Ia models, where dynamical interaction between two sub-M-Ch white dwarfs (WDs) causes disruption of the lower-mass WD and detonation of the other. The violent merger scenario was already a leading hypothesis for 03fg-like SNe Ia; in SN 2022pul it can explain the large-scale ejecta asymmetries seen between the IMEs and IGEs and the central location of narrow oxygen and broad neon. We modify extant models to add clumping of the ejecta to reproduce the optical iron emission better, and add mass in the innermost region (<2000 km s(-1)) to account for the observed narrow [O i] lambda lambda 6300, 6364 emission. A violent WD-WD merger explains many of the observations of SN 2022pul, and our results favor this model interpretation for the subclass of 03fg-like SNe Ia.
- ItemLooking for the Building Blocks of the Galactic Halo: Variable stars in the Fornax, Bootes I, Canes Venatici II Dwarfs and in NGC2419(2009) Greco, Claudia; Clementini, Gisella; Held, Enrico E.; Poretti, Ennio; Catelan, Márcio; Federici, Luciana; Gullieuszik, Marco; Maio, Marcella; Ripepi, Vincenzo; Dall'Ora, Massimo; di Fabrizio, Luca; Kinemuchi, Karen; di Criscienzo, Marcella; Marconi, Marcella; Musella, Ilaria; Rest, Armin; de Lee, Nathan; Pritzl, Barton J.; Smith, HoraceLooking for the building blocks of the Galactic Halo we have investigated and compared the properties of the RR Lyrae stars in a number of different stellar systems inside and outside the Milky Way.
- ItemThe Gravity Collective: A Search for the Electromagnetic Counterpart to the Neutron Star-Black Hole Merger GW190814(2021) Kilpatrick, Charles D.; Coulter, David A.; Arcavi, Iair; Brink, Thomas G.; Dimitriadis, Georgios; Filippenko, Alexei, V; Foley, Ryan J.; Howell, D. Andrew; Jones, David O.; Kasen, Daniel; Makler, Martin; Piro, Anthony L.; Rojas-Bravo, Cesar; Sand, David J.; Swift, Jonathan J.; Tucker, Douglas; Zheng, WeiKang; Allam, Sahar S.; Annis, James T.; Antilen, Juanita; Bachmann, Tristan G.; Bloom, Joshua S.; Bom, Clecio R.; Bostroem, K. Azalee; Brout, Dillon; Burke, Jamison; Butler, Robert E.; Butner, Melissa; Campillay, Abdo; Clever, Karoli E.; Conselice, Christopher J.; Cooke, Jeff; Dage, Kristen C.; de Carvalho, Reinaldo R.; de Jaeger, Thomas; Desai, Shantanu; Garcia, Alyssa; Garcia-Bellido, Juan; Gill, Mandeep S. S.; Girish, Nachiket; Hallakoun, Na'ama; Herner, Kenneth; Hiramatsu, Daichi; Holz, Daniel E.; Huber, Grace; Kawash, Adam M.; McCully, Curtis; Medallon, Sophia A.; Metzger, Brian D.; Modak, Shaunak; Morgan, Robert; Munoz, Ricardo R.; Munoz-Elgueta, Nahir; Murakami, Yukei S.; Felipe Olivares, E.; Palmese, Antonella; Patra, Kishore C.; Pereira, Maria E. S.; Pessi, Thallis L.; Pineda-Garcia, J.; Quirola-Vasquez, Jonathan; Ramirez-Ruiz, Enrico; Rembold, Sandro Barboza; Rest, Armin; Rodriguez, Osmar; Santana-Silva, Luidhy; Sherman, Nora F.; Siebert, Matthew R.; Smith, Carli; Smith, J. Allyn; Soares-Santos, Marcelle; Stacey, Holland; Stahl, Benjamin E.; Strader, Jay; Strasburger, Erika; Sunseri, James; Tinyanont, Samaporn; Tucker, Brad E.; Ulloa, Natalie; Valenti, Stefano; Vasylyev, Sergiy S.; Wiesner, Matthew P.; Zhang, Keto D.We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of the LIGO/Virgo gravitational wave (GW) signal from the neutron star-black hole (NSBH) merger GW190814. We searched the GW190814 localization region (19 deg(2) for the 90th percentile best localization), covering a total of 51 deg(2) and 94.6% of the two-dimensional localization region. Analyzing the properties of 189 transients that we consider as candidate counterparts to the NSBH merger, including their localizations, discovery times from merger, optical spectra, likely host galaxy redshifts, and photometric evolution, we conclude that none of these objects are likely to be associated with GW190814. Based on this finding, we consider the likely optical properties of an electromagnetic counterpart to GW190814, including possible kilonovae and short gamma-ray burst afterglows. Using the joint limits from our follow-up imaging, we conclude that a counterpart with an r-band decline rate of 0.68 mag day(-1), similar to the kilonova AT 2017gfo, could peak at an absolute magnitude of at most -17.8 mag (50% confidence). Our data are not constraining for "red" kilonovae and rule out "blue" kilonovae with M > 0.5 M (circle dot) (30% confidence). We strongly rule out all known types of short gamma-ray burst afterglows with viewing angles <17 degrees assuming an initial jet opening angle of similar to 5.degrees 2 and explosion energies and circumburst densities similar to afterglows explored in the literature. Finally, we explore the possibility that GW190814 merged in the disk of an active galactic nucleus, of which we find four in the localization region, but we do not find any candidate counterparts among these sources.
- ItemVariable stars in the fornax dsph galaxy. I. The globular cluster fornax(2007) Greco, Claudia; Clementini, Gisella; Catelan, Marcio; Held, Enrico V.; Poretti, Ennio; Gullieuszik, Marco; Maio, Marcella; Rest, Armin; De Lee, Nathan; Smith, Horace A.; Pritzl, Barton J.Variable stars have been identified for the first time in Fornax 4, the globular cluster located near the center of the Fornax dwarf spheroidal galaxy. By applying the image-subtraction technique to B and V time series photometry obtained with the MagIC camera of the 6.5m Magellan Clay telescope and with the wide field imager of the 4 m Blanco CTIO telescope, we detected 27 RR Lyrae stars (22 fundamental-mode, 3 first-overtone, and 2 double-mode pulsators) in a 2.4' x 2.4' area centered on Fornax 4. The average and minimum periods of the ab-type RR Lyrae stars, < Pab > = 0: 594 days and P(ab,min) = 0.5191 days, respectively, as well as the revised position of the cluster in the horizontal branch type-metallicity plane, all consistently point to an Oosterhoff-intermediate status for the cluster, unlike what is seen for the vast majority of Galactic globular clusters, but in agreement with previous indications for the other globular clusters in Fornax. The average apparent magnitude of the RR Lyrae stars located within 3000 from the cluster center is < V(RR)> = 21.43 +/- 0.03 mag (sigma = 0.10 mag, average of 12 stars), leading to a true distance modulus of mu(0) = 20.64 +/- 0.09 mag or mu(0) = 20.53 +/- 0.09 mag, depending on whether a low ([Fe/H] = -2.0) or a moderately high ([Fe/H] = -1: 5) metallicity is adopted.