374 results on '"Filippenko, Alexei V"'
Search Results
2. JWST NIRSpec Spectroscopy of the Remarkable Bright Galaxy GHZ2/GLASS-z12 at Redshift 12.34.
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Castellano, Marco, Napolitano, Lorenzo, Fontana, Adriano, Roberts-Borsani, Guido, Treu, Tommaso, Vanzella, Eros, Zavala, Jorge A., Arrabal Haro, Pablo, Calabrò, Antonello, Llerena, Mario, Mascia, Sara, Merlin, Emiliano, Paris, Diego, Pentericci, Laura, Santini, Paola, Bakx, Tom J. L. C., Bergamini, Pietro, Cupani, Guido, Dickinson, Mark, and Filippenko, Alexei V.
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STELLAR density (Stellar population) ,ROSETTA Stone ,ACTIVE galactic nuclei ,GALACTIC redshift ,GALAXY formation - Abstract
We spectroscopically confirm the M
UV = −20.5 mag galaxy GHZ2/GLASS-z12 to be at redshift z = 12.34. The source was selected via NIRCam photometry in GLASS-JWST Early Release Science data, providing the first evidence of a surprising abundance of bright galaxies at z ≳ 10. The NIRSpec PRISM spectrum shows detections of N iv, C iv, He ii, O iii, C iii, O ii, and Ne iii lines and the first detection at high redshift of the O iii Bowen fluorescence line at 3133 Å rest frame. The prominent C iv line with rest-frame equivalent width (EW) ≈ 46 Å puts GHZ2 in the category of extreme C iv emitters. GHZ2 displays UV lines with EWs that are only found in active galactic nuclei (AGNs) or composite objects at low/intermediate redshifts. The UV line-intensity ratios are compatible with both AGNs and star formation in a low-metallicity environment, with the low limit on the [Ne iv ]/[N iv ] ratio favoring a stellar origin of the ionizing photons. We discuss a possible scenario in which the high ionizing output is due to low-metallicity stars forming in a dense environment. We estimate a metallicity ≲0.1 Z / Z⊙ , a high ionization parameter log U > −2, a N/O abundance 4–5 times the solar value, and a subsolar C/O ratio similar to the recently discovered class of nitrogen-enhanced objects. Considering its abundance patterns and the high stellar mass density (104 M⊙ pc−2 ), GHZ2 is an ideal formation site for the progenitors of today's globular clusters. The remarkable brightness of GHZ2 makes it a "Rosetta stone" for understanding the physics of galaxy formation within just 360 Myr after the Big Bang. [ABSTRACT FROM AUTHOR]- Published
- 2024
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3. AGN STORM 2. VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations.
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Dehghanian, Maryam, Arav, Nahum, Kriss, Gerard A., Mehdipour, Missagh, Byun, Doyee, Walker, Gwen, Sharma, Mayank, Barth, Aaron J., Bentz, Misty C., Boizelle, Benjamin D., Brotherton, Michael S., Cackett, Edward M., Dalla Bontà, Elena, De Rosa, Gisella, Ferland, Gary J., Fian, Carina, Filippenko, Alexei V., Gelbord, Jonathan, Goad, Michael R., and Horne, Keith
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ACTIVE galactic nuclei ,SEYFERT galaxies ,ACTIVE galaxies ,SPACE telescopes ,SPECTROGRAPHS - Abstract
We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the narrow absorption outflow system (at −3750 km s
−1 with FWHM = 177 km s−1 ) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (log NH = 19.5 − 0.13 + 0.61 cm−2 ) did not change across all epochs. The adjusted ionization parameter (scaled with respect to the variations in the hydrogen-ionizing continuum flux) is log UH = −1.0 − 0.3 + 0.1 . The outflow is located at a distance smaller than 38 pc from the central source, which implies a hydrogen density of nH > 3000 cm−3 . The absorption outflow system only covers the continuum emission source and not the broad emission line region, which suggests that its transverse size is small (< 1016 cm), with potential cloud geometries ranging from spherical to elongated along the line of sight. [ABSTRACT FROM AUTHOR]- Published
- 2024
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4. Ejecta Masses in Type Ia Supernovae—Implications for the Progenitor and the Explosion Scenario.
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Bora, Zsófia, Könyves-Tóth, Réka, Vinkó, József, Bánhidi, Dominik, Bíró, Imre Barna, Bostroem, K. Azalee, Bódi, Attila, Burke, Jamison, Csányi, István, Cseh, Borbála, Farah, Joseph, Filippenko, Alexei V., Hegedüs, Tibor, Hiramatsu, Daichi, Horti-Dávid, Ágoston, Howell, D. Andrew, Jha, Saurabh W., Kalup, Csilla, Krezinger, Máté, and Kriskovics, Levente
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TYPE I supernovae ,RADIATIVE transfer ,NUCLEOSYNTHESIS ,SUPERNOVAE ,ASTROPHYSICS - Abstract
The progenitor system(s) as well as the explosion mechanism(s) of thermonuclear (Type Ia) supernovae are long-standing issues in astrophysics. Here we present ejecta masses and other physical parameters for 28 recent Type Ia supernovae inferred from multiband photometric and optical spectroscopic data. Our results confirm that the majority of SNe Ia show observable ejecta masses below the Chandrasekhar-limit (having a mean M
ej ≈ 1.1 ± 0.3 M⊙ ), consistent with the predictions of recent sub- MCh explosion models. They are compatible with models assuming either single- or double-degenerate progenitor configurations. We also recover a sub-sample of supernovae within 1.2 M⊙ < Mej < 1.5 M⊙ that are consistent with near-Chandrasekhar explosions. Taking into account the uncertainties of the inferred ejecta masses, about half of our SNe are compatible with both explosion models. We compare our results with those in previous studies, and discuss the caveats and concerns regarding the applied methodology. [ABSTRACT FROM AUTHOR]- Published
- 2024
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5. Flashlights: Properties of highly magnified Images near cluster critical curves in the presence of dark matter subhalos
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Space Telescope Science Institute (US), National Aeronautics and Space Administration (US), National Science Foundation (US), Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Ciencia e Innovación (España), Christopher R. Redlich Fund, United States-Israel Binational Science Foundation, Ministry of Science and Technology (Israel), Williams, Liliya L. R., Kelly, Patrick L., Treu, Tommaso, Amruth, Alfred, Diego, José María, Li, Sung Kei, Meena, Ashish K., Zitrin, Adi, Broadhurst, Tom, Filippenko, Alexei V., Space Telescope Science Institute (US), National Aeronautics and Space Administration (US), National Science Foundation (US), Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Ciencia e Innovación (España), Christopher R. Redlich Fund, United States-Israel Binational Science Foundation, Ministry of Science and Technology (Israel), Williams, Liliya L. R., Kelly, Patrick L., Treu, Tommaso, Amruth, Alfred, Diego, José María, Li, Sung Kei, Meena, Ashish K., Zitrin, Adi, Broadhurst, Tom, and Filippenko, Alexei V.
- Abstract
Dark matter subhalos with extended profiles and density cores, and globular star clusters of mass 106–108M⊙ that live near the critical curves in galaxy cluster lenses can potentially be detected through their lensing magnification of stars in background galaxies. In this work, we study the effect such subhalos have on lensed images, and compare to the case of more well-studied microlensing by stars and black holes near critical curves. We find that the cluster density gradient and the extended mass distribution of subhalos are important in determining image properties. Both lead to an asymmetry between the image properties on the positive- and negative-parity sides of the cluster that is more pronounced than in the case of microlensing. For example, on the negative-parity side, subhalos with cores larger than about 50 pc do not generate any images with magnification above ∼100 outside of the immediate vicinity of the cluster critical curve. We discuss these factors using analytical and numerical analysis, and exploit them to identify observable signatures of subhalos: Subhalos create pixel-to-pixel flux variations of ≳0.1 mag on the positive-parity side of clusters. These pixels tend to cluster around (otherwise invisible) subhalos. Unlike in the case of microlensing, signatures of subhalo lensing can be found up to 1'' away from the critical curves of massive clusters.
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- 2024
6. Sp1149. II. Spectroscopy of H ii Regions near the Critical Curve of MACS J1149 and Cluster Lens Models.
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Williams, Hayley, Kelly, Patrick, Chen, Wenlei, Diego, Jose M., Oguri, Masamune, and Filippenko, Alexei V.
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HUBBLE constant ,SPECTROMETRY ,GALACTIC redshift ,GALAXY clusters ,PREDICTION models ,GALAXIES ,GRAVITATIONAL lenses - Abstract
Galaxy-cluster gravitational lenses enable the study of faint galaxies even at large lookback times, and, recently, time-delay constraints on the Hubble constant. There have been few tests, however, of lens model predictions adjacent to the critical curve (≲8″) where the magnification is greatest. In a companion paper, we use the GLAFIC lens model to constrain the Balmer L – σ relation for H ii regions in a galaxy at redshift z = 1.49 strongly lensed by the MACS J1149 galaxy cluster. Here we perform a detailed comparison between the predictions of 10 cluster lens models that employ multiple modeling assumptions with our measurements of 11 magnified, giant H ii regions. We find that that the models predict magnifications an average factor of 6.2 smaller, a ∼2 σ tension, than that inferred from the H ii regions under the assumption that they follow the low-redshift L – σ relation. To evaluate the possibility that the lens model magnifications are strongly biased, we next consider the flux ratios among knots in three images of Sp1149, and find that these are consistent with model predictions. Moreover, while the mass-sheet degeneracy could in principle account for a factor of ∼6 discrepancy in magnification, the value of H
0 inferred from SN Refsdal's time delay would become implausibly small. We conclude that the lens models are not likely to be highly biased, and that instead the H ii regions in Sp1149 are substantially more luminous than the low-redshift Balmer L – σ relation predicts. [ABSTRACT FROM AUTHOR]- Published
- 2024
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7. Leveraging SN Ia spectroscopic similarity to improve the measurement of H 0
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Murakami, Yukei S., primary, Riess, Adam G., additional, Stahl, Benjamin E., additional, D'Arcy Kenworthy, W., additional, Pluck, Dahne-More A., additional, Macoretta, Antonella, additional, Brout, Dillon, additional, Jones, David O., additional, Scolnic, Dan M., additional, and Filippenko, Alexei V., additional
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- 2023
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8. SN 2022oqm–A Ca-rich Explosion of a Compact Progenitor Embedded in C/O Circumstellar Material.
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Irani, Ido, Chen, Ping, Morag, Jonathan, Schulze, Steve, Gal-Yam, Avishay, Strotjohann, Nora L., Yaron, Ofer, Zimmerman, Erez A., Sharon, Amir, Perley, Daniel A., Sollerman, J., Tohuvavohu, Aaron, Das, Kaustav K., Kasliwal, Mansi M., Bruch, Rachel, Brink, Thomas G., Zheng, WeiKang, Filippenko, Alexei V., Patra, Kishore C., and Vasylyev, Sergiy S.
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LIGHT curves ,WOLF-Rayet stars ,STELLAR photospheres ,SUPERGIANT stars ,TYPE I supernovae ,ULTRAVIOLET astronomy ,CIRCUMSTELLAR matter - Abstract
We present the discovery and analysis of SN 2022oqm, a Type Ic supernova (SN) detected <1 day after the explosion. The SN rises to a blue and short-lived (2 days) initial peak. Early-time spectral observations of SN 2022oqm show a hot (40,000 K) continuum with high ionization C and O absorption features at velocities of 4000 km s
−1 , while its photospheric radius expands at 20,000 km s−1 , indicating a pre-existing distribution of expanding C/O material. After ∼2.5 days, both the spectrum and light curves evolve into those of a typical SN Ic, with line velocities of ∼10,000 km s−1 , in agreement with the evolution of the photospheric radius. The optical light curves reach a second peak at t ≈ 15 days. By t = 60 days, the spectrum of SN 2022oqm becomes nearly nebular, displaying strong Ca ii and [Ca ii ] emission with no detectable [O i ], marking this event as Ca-rich. The early behavior can be explained by 10−3 M⊙ of optically thin circumstellar material (CSM) surrounding either (1) a massive compact progenitor such as a Wolf–Rayet star, (2) a massive stripped progenitor with an extended envelope, or (3) a binary system with a white dwarf. We propose that the early-time light curve is powered by both the interaction of the ejecta with the optically thin CSM and shock cooling (in the massive star scenario). The observations can be explained by CSM that is optically thick to X-ray photons, is optically thick in the lines as seen in the spectra, and is optically thin to visible-light continuum photons that come either from downscattered X-rays or from the shock-heated ejecta. Calculations show that this scenario is self-consistent. [ABSTRACT FROM AUTHOR]- Published
- 2024
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9. Evolution of the mass-metallicity relation from redshift z ≈ 8 to the local universe
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National Aeronautics and Space Administration (US), Villum Fonden, National Science Foundation (US), United States-Israel Binational Science Foundation, Ministerio de Ciencia e Innovación (España), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Japan Society for the Promotion of Science, Gordon and Betty Moore Foundation, David and Lucile Packard Foundation, Langeroodi, Danial, Hjorth, Jens, Chen, Wenlei, Kelly, Patrick L., Williams, Hayley, Lin, Yu-Heng, Scarlata, Claudia, Zitrin, Adi, Broadhurst, Tom, Diego, José María, Huang, Xiaosheng, Filippenko, Alexei V., Foley, Ryan J., Jha, Saurabh W., Koekemoer, Anton M., Oguri, Masamune, Pèrez-Fournon, Ismael, Pierel, Justin, Poidevin, Frédérick, Strolger, Lou G., National Aeronautics and Space Administration (US), Villum Fonden, National Science Foundation (US), United States-Israel Binational Science Foundation, Ministerio de Ciencia e Innovación (España), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Japan Society for the Promotion of Science, Gordon and Betty Moore Foundation, David and Lucile Packard Foundation, Langeroodi, Danial, Hjorth, Jens, Chen, Wenlei, Kelly, Patrick L., Williams, Hayley, Lin, Yu-Heng, Scarlata, Claudia, Zitrin, Adi, Broadhurst, Tom, Diego, José María, Huang, Xiaosheng, Filippenko, Alexei V., Foley, Ryan J., Jha, Saurabh W., Koekemoer, Anton M., Oguri, Masamune, Pèrez-Fournon, Ismael, Pierel, Justin, Poidevin, Frédérick, and Strolger, Lou G.
- Abstract
A tight positive correlation between the stellar mass and the gas-phase metallicity of galaxies has been observed at low redshifts. The redshift evolution of this correlation can strongly constrain theories of galaxy evolution. The advent of JWST allows probing the mass–metallicity relation at redshifts far beyond what was previously accessible. Here we report the discovery of two emission line galaxies at redshifts 8.15 and 8.16 in JWST NIRCam imaging and NIRSpec spectroscopy of targets gravitationally lensed by the cluster RX J2129.4+0005. We measure their metallicities and stellar masses along with nine additional galaxies at 7.2 < zspec < 9.5 to report the first quantitative statistical inference of the mass–metallicity relation at z ≈ 8. We measure ∼0.9 dex evolution in the normalization of the mass–metallicity relation from z ≈ 8 to the local universe; at a fixed stellar mass, galaxies are 8 times less metal enriched at z ≈ 8 compared to the present day. Our inferred normalization is in agreement with the predictions of FIRE simulations. Our inferred slope of the mass–metallicity relation is similar to or slightly shallower than that predicted by FIRE or observed at lower redshifts. We compare the z ≈ 8 galaxies to extremely low-metallicity analog candidates in the local universe, finding that they are generally distinct from extreme emission line galaxies or "green peas," but are similar in strong emission line ratios and metallicities to "blueberry galaxies." Despite this similarity, at a fixed stellar mass, the z ≈ 8 galaxies have systematically lower metallicities compared to blueberry galaxies.
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- 2023
10. SN 2016ije: An SN 2002es-like Type Ia Supernova Exploded in a Metal-poor and Low-surface Brightness Galaxy.
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Li, Zhitong, Zhang, Tianmeng, Wang, Xiaofeng, Zhang, Jujia, Galbany, Lluís, Filippenko, Alexei V., Brink, Thomas G., Ashall, Chris, Zheng, WeiKang, de Jaeger, Thomas, Ragosta, Fabio, Deckers, Maxime, Gromadzki, Mariusz, Young, D. R., Xi, Gaobo, Chen, Juncheng, Zhao, Xulin, Sai, Hanna, Yan, Shengyu, and Xiang, Danfeng
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TYPE I supernovae ,GALACTIC magnitudes ,SURFACE brightness (Astronomy) ,LIGHT curves - Abstract
We have conducted photometric and spectroscopic observations of the peculiar Type Ia supernova (SN Ia) 2016ije that was discovered through the Tsinghua-NAOC Transient Survey. This peculiar object exploded in the outskirts of a metal-poor, low-surface brightness galaxy (i.e., M
g = −14.5 mag). Our photometric analysis reveals that SN 2016ije is subluminous ( M B , max = −17.65 ± 0.06 mag) but exhibits relatively broad light curves (Δ m15 (B) = 1.35 ± 0.14 mag), similar to the behavior of SN 2002es. Our analysis of the bolometric light curve indicates that only 0.14 ± 0.04 M⊙ of56 Ni was synthesized in the explosion of SN 2016ije, which suggests a less energetic thermonuclear explosion when compared to normal SNe Ia, and this left a considerable amount of unburned materials in the ejecta. Spectroscopically, SN 2016ije resembles other SN 2002es-like SNe Ia, except that the ejecta velocity inferred from its carbon absorption line (∼4500 km s−1 ) is much lower than that from silicon lines (∼8300 km s−1 ) at around the maximum light. Additionally, most of the absorption lines are broader than other 02es-like SNe Ia. These peculiarities suggest the presence of significant unburned carbon in the inner region and a wide line-forming region along the line of sight. These characteristics suggest that SN 2016ije might originate from the violent merger of a white dwarf binary system, when viewed near an orientation along the iron-group-element cavity caused by the companion star. [ABSTRACT FROM AUTHOR]- Published
- 2023
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11. The Magnificent Five Images of Supernova Refsdal: Time Delay and Magnification Measurements.
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Kelly, Patrick L., Rodney, Steven, Treu, Tommaso, Birrer, Simon, Bonvin, Vivien, Dessart, Luc, Foley, Ryan J., Filippenko, Alexei V., Gilman, Daniel, Jha, Saurabh, Hjorth, Jens, Mandel, Kaisey, Millon, Martin, Pierel, Justin, Thorp, Stephen, Zitrin, Adi, Broadhurst, Tom, Chen, Wenlei, Diego, Jose M., and Dressler, Alan
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SUPERNOVAE ,TYPE II supernovae - Abstract
In late 2014, four images of supernova (SN) "Refsdal," the first known example of a strongly lensed SN with multiple resolved images, were detected in the MACS J1149 galaxy-cluster field. Following the images' discovery, the SN was predicted to reappear within hundreds of days at a new position ∼8″ away in the field. The observed reappearance in late 2015 makes it possible to carry out Refsdal's original proposal to use a multiply imaged SN to measure the Hubble constant H
0 , since the time delay between appearances should vary inversely with H0 . Moreover, the position, brightness, and timing of the reappearance enable a novel test of the blind predictions of galaxy-cluster models, which are typically constrained only by the positions of multiply imaged galaxies. We have developed a new photometry pipeline that uses DOLPHOT to measure the fluxes of the five images of SN Refsdal from difference images. We apply four separate techniques to perform a blind measurement of the relative time delays and magnification ratios between the last image SX and the earlier images S1–S4. We measure the relative time delay of SX–S1 to be 376.0 − 5.5 + 5.6 days and the relative magnification to be 0.30 − 0.3 + 0.5 . This corresponds to a 1.5% precision on the time delay and 17% precision for the magnification ratios and includes uncertainties due to millilensing and microlensing. In an accompanying paper, we place initial and blind constraints on the value of the Hubble constant. [ABSTRACT FROM AUTHOR]- Published
- 2023
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12. What Does the Geometry of the H β BLR Depend On?
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Villafaña, Lizvette, Williams, Peter R., Treu, Tommaso, Brewer, Brendon J., Barth, Aaron J., U, Vivian, Bennert, Vardha N., Guo, Hengxiao, Bentz, Misty C., Canalizo, Gabriela, Filippenko, Alexei V., Gates, Elinor, Joner, Michael D., Malkan, Matthew A., Woo, Jong-Hak, Abolfathi, Bela, Bohn, Thomas, Bostroem, K. Azalee, Brandel, Andrew, and Brink, Thomas G.
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VIRIAL coefficients ,ACTIVE galactic nuclei ,SUPERMASSIVE black holes - Abstract
We combine our dynamical modeling black-hole mass measurements from the Lick AGN Monitoring Project 2016 sample with measured cross-correlation time lags and line widths to recover individual scale factors, f, used in traditional reverberation-mapping analyses. We extend our sample by including prior results from Code for AGN Reverberation and Modeling of Emission Lines (caramel) studies that have utilized our methods. Aiming to improve the precision of black-hole mass estimates, as well as uncover any regularities in the behavior of the broad-line region (BLR), we search for correlations between f and other AGN/BLR parameters. We find (i) evidence for a correlation between the virial coefficient log 10 (f mean , σ) and black-hole mass, (ii) marginal evidence for a similar correlation between log 10 (f rms , σ) and black-hole mass, (iii) marginal evidence for an anticorrelation of BLR disk thickness with log 10 (f mean , FWHM) and log 10 (f rms , FWHM) , and (iv) marginal evidence for an anticorrelation of inclination angle with log 10 (f mean , FWHM) , log 10 (f rms , σ) , and log 10 (f mean , σ). Last, we find marginal evidence for a correlation between line-profile shape, when using the root-mean-square spectrum, log 10 (FWHM / σ) rms , and the virial coefficient, log 10 (f rms , σ) , and investigate how BLR properties might be related to line-profile shape using caramel models. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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13. Spectropolarimetry of the thermonuclear supernova SN 2021rhu: High calcium polarization 79 days after peak luminosity
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Swedish Research Council, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), European Research Council, European Commission, Consejo Superior de Investigaciones Científicas (España), Yang, Yi, Yan, Huirong, Wang, Lifan, Wheeler, J. Craig, Baade, Dietrich, Isaacson, Howard, Cikota, Aleksandar, Maund, Justyn R., Hoeflich, Peter, Patat, Ferdinando, Giacalone, Steven, Rice, Malena, Tyler, Dakotah B., Mishra, Divya, Ashall, Chris, Brink, Thomas G., Filippenko, Alexei V., Galbany, Lluís, Patra, Kishore C., Shahbandeh, Melissa, Vasylyev, Sergiy S., Vinkó, Jozsef, Swedish Research Council, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), European Research Council, European Commission, Consejo Superior de Investigaciones Científicas (España), Yang, Yi, Yan, Huirong, Wang, Lifan, Wheeler, J. Craig, Baade, Dietrich, Isaacson, Howard, Cikota, Aleksandar, Maund, Justyn R., Hoeflich, Peter, Patat, Ferdinando, Giacalone, Steven, Rice, Malena, Tyler, Dakotah B., Mishra, Divya, Ashall, Chris, Brink, Thomas G., Filippenko, Alexei V., Galbany, Lluís, Patra, Kishore C., Shahbandeh, Melissa, Vasylyev, Sergiy S., and Vinkó, Jozsef
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We report spectropolarimetric observations of the Type Ia supernova (SN) SN 2021rhu at four epochs: −7, +0, +36, and +79 days relative to its B-band maximum luminosity. A wavelength-dependent continuum polarization peaking at 3890 ±93Å and reaching a level of pmax = 1.78% 0.02 %was found. The peak of the polarization curve is bluer than is typical in the Milky Way, indicating a larger proportion of small dust grains along the sight line to the SN. After removing the interstellar polarization, we found a pronounced increase of the polarization in the CaII near-infrared triplet, from ∼0.3% at day −7to∼2.5% at day +79. No temporal evolution in highresolution flux spectra across the Na I D and Ca II H and K features was seen from days +39 to +74, indicating that the late-time increase in polarization is intrinsic to the SN as opposed to being caused by scattering of SN photons in circumstellar or interstellar matter. We suggest that an explanation for the late-time rise of the Ca II near-infrared triplet polarization may be the alignment of calcium atoms in a weak magnetic field through optical excitation/ pumping by anisotropic radiation from the SN.
- Published
- 2022
14. Early Results from GLASS-JWST. XIV. A Spectroscopically Confirmed Protocluster 650 Million Years after the Big Bang.
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Morishita, Takahiro, Roberts-Borsani, Guido, Treu, Tommaso, Brammer, Gabriel, Mason, Charlotte A., Trenti, Michele, Vulcani, Benedetta, Wang, Xin, Acebron, Ana, Bahé, Yannick, Bergamini, Pietro, Boyett, Kristan, Bradac, Marusa, Calabrò, Antonello, Castellano, Marco, Chen, Wenlei, De Lucia, Gabriella, Filippenko, Alexei V., Fontana, Adriano, and Glazebrook, Karl
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- 2023
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15. PSR J0952â'0607: The Fastest and Heaviest Known Galactic Neutron Star.
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Romani, Roger W., Kandel, D., Filippenko, Alexei V., Brink, Thomas G., and Zheng, WeiKang
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- 2022
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16. A Comprehensive Measurement of the Local Value of the Hubble Constant with 1 km s â'1 Mpc â'1 Uncertainty from the Hubble Space Telescope and the SH0ES Team.
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Riess, Adam G., Yuan, Wenlong, Macri, Lucas M., Scolnic, Dan, Brout, Dillon, Casertano, Stefano, Jones, David O., Murakami, Yukei, Anand, Gagandeep S., Breuval, Louise, Brink, Thomas G., Filippenko, Alexei V., Hoffmann, Samantha, Jha, Saurabh W., D’arcy Kenworthy, W., Mackenty, John, Stahl, Benjamin E., and Zheng, WeiKang
- Published
- 2022
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17. Early-time Ultraviolet Spectroscopy and Optical Follow-up Observations of the Type IIP Supernova 2021yja.
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Vasylyev, Sergiy S., Filippenko, Alexei V., Vogl, Christian, Brink, Thomas G., Brown, Peter J., Jaeger, Thomas de, Matheson, Thomas, Gal-Yam, Avishay, Mazzali, Paolo A., Modjaz, Maryam, Patra, Kishore C., Rowe, Micalyn, Smith, Nathan, Van Dyk, Schuyler D., Williamson, Marc, Yang, Yi, Zheng, WeiKang, deGraw, Asia, Fox, Ori D., and Gates, Elinor L.
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OPTICAL spectroscopy , *ULTRAVIOLET spectroscopy , *SUPERNOVAE , *TYPE II supernovae , *RADIATIVE transfer , *PHOTOMETRY - Abstract
We present three epochs of early-time ultraviolet (UV) and optical HST/STIS spectroscopy of the young, nearby Type IIP supernova (SN) 2021yja. We complement the HST data with two earlier epochs of Swift UVOT spectroscopy. The HST and Swift UVOT spectra are consistent with those of other well-studied Type IIP SNe. The UV spectra exhibit rapid cooling at early times, while less dramatic changes are seen in the optical. We also present Lick/KAIT optical photometry up to the late-time tail phase, showing a very long plateau and shallow decline compared with other SNe IIP. Our modeling of the UV spectrum with the TARDIS radiative transfer code produces a good fit for a high-velocity explosion, a low total extinction E (B â' V) = 0.07 mag, and a subsolar metallicity. We do not find a significant contribution to the UV flux from an additional heating source, such as interaction with the circumstellar medium, consistent with the observed flat plateau. Furthermore, the velocity width of the Mg ii λ 2798 line is comparable to that of the hydrogen Balmer lines, suggesting that the UV emission is confined to a region close to the photosphere. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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18. Investigating the Nature of the Luminous Ambiguous Nuclear Transient ASASSN-17jz.
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Holoien, Thomas W.-S., Neustadt, Jack M. M., Vallely, Patrick J., Auchettl, Katie, Hinkle, Jason T., Romero-Cañizales, Cristina, Shappee, Benjamin. J., Kochanek, Christopher S., Stanek, K. Z., Chen, Ping, Dong, Subo, Prieto, Jose L., Thompson, Todd A., Brink, Thomas G., Filippenko, Alexei V., Zheng, WeiKang, Bersier, David, Bose, Subhash, Burgasser, Adam J., and Channa, Sanyum
- Subjects
ACTIVE galactic nuclei ,SPECTRAL lines - Abstract
We present observations of the extremely luminous but ambiguous nuclear transient (ANT) ASASSN-17jz, spanning roughly 1200 days of the object’s evolution. ASASSN-17jz was discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) in the galaxy SDSS J171955.84+414049.4 on UT 2017 July 27 at a redshift of z = 0.1641. The transient peaked at an absolute B -band magnitude of M
B,peak = â'22.81, corresponding to a bolometric luminosity of Lbol,peak = 8.3 Ă— 1044 erg sâ'1 , and exhibited late-time ultraviolet emission that was still ongoing in our latest observations. Integrating the full light curve gives a total emitted energy of Etot = (1.36 ±0.08) Ă— 1052 erg, with (0.80 ± 0.02) Ă— 1052 erg of this emitted within 200 days of peak light. This late-time ultraviolet emission is accompanied by increasing X-ray emission that becomes softer as it brightens. ASASSN-17jz exhibited a large number of spectral emission lines most commonly seen in active galactic nuclei (AGNs) with little evidence of evolution. It also showed transient Balmer features, which became fainter and broader over time, and are still being detected >1000 days after peak brightness. We consider various physical scenarios for the origin of the transient, including supernovae (SNe), tidal disruption events, AGN outbursts, and ANTs. We find that the most likely explanation is that ASASSN-17jz was a SN IIn occurring in or near the disk of an existing AGN, and that the late-time emission is caused by the AGN transitioning to a more active state. [ABSTRACT FROM AUTHOR]- Published
- 2022
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19. The Lick AGN Monitoring Project 2016: Dynamical Modeling of Velocity-resolved H β Lags in Luminous Seyfert Galaxies.
- Author
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Villafaña, Lizvette, Williams, Peter R., Treu, Tommaso, Brewer, Brendon J., Barth, Aaron J., U, Vivian, Bennert, Vardha N., Alexander Vogler, H., Guo, Hengxiao, Bentz, Misty C., Canalizo, Gabriela, Filippenko, Alexei V., Gates, Elinor, Hamann, Frederick, Joner, Michael D., Malkan, Matthew A., Woo, Jong-Hak, Abolfathi, Bela, Abramson, L. E., and Armen, Stephen F.
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ACTIVE galactic nuclei ,SUPERMASSIVE black holes ,SEYFERT galaxies ,ACTIVE galaxies - Abstract
We have modeled the velocity-resolved reverberation response of the H β broad emission line in nine Seyfert 1 galaxies from the Lick Active Galactic Nucleus (AGN) Monitoring Project 2016 sample, drawing inferences on the geometry and structure of the low-ionization broad-line region (BLR) and the mass of the central supermassive black hole. Overall, we find that the H β BLR is generally a thick disk viewed at low to moderate inclination angles. We combine our sample with prior studies and investigate line-profile shape dependence, such as log 10 (FWHM / Ď) , on BLR structure and kinematics and search for any BLR luminosity-dependent trends. We find marginal evidence for an anticorrelation between the profile shape of the broad H β emission line and the Eddington ratio, when using the rms spectrum. However, we do not find any luminosity-dependent trends, and conclude that AGNs have diverse BLR structure and kinematics, consistent with the hypothesis of transient AGN/BLR conditions rather than systematic trends. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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- View/download PDF
20. The Candidate Progenitor Companion Star of the Type Ib/c SN 2013ge.
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Fox, Ori D., Van Dyk, Schuyler D., Williams, Benjamin F., Drout, Maria, Zapartas, Emmanouil, Smith, Nathan, Milisavljevic, Dan, Andrews, Jennifer E., Bostroem, K. Azalee, Filippenko, Alexei V., Gomez, Sebastian, Kelly, Patrick L., de Mink, S. E., Pierel, Justin, Rest, Armin, Ryder, Stuart, Sravan, Niharika, Strolger, Lou, Wang, Qinan, and Weil, Kathryn E.
- Published
- 2022
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21. Optical Rebrightening of Extragalactic Transients from the Zwicky Transient Facility.
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Soraisam, Monika, Matheson, Thomas, Lee, Chien-Hsiu, Saha, Abhijit, Narayan, Gautham, Wolf, Nicholas, Scott, Adam, Figuereo, Stephanie, Nuńez, Rafael, McKinnon, Kevin, Guhathakurta, Puragra, Brink, Thomas G., Filippenko, Alexei V., and Smith, Nathan
- Published
- 2022
- Full Text
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22. The Lick AGN Monitoring Project 2016: Velocity-resolved H β Lags in Luminous Seyfert Galaxies.
- Author
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U, Vivian, Barth, Aaron J., Vogler, H. Alexander, Guo, Hengxiao, Treu, Tommaso, Bennert, Vardha N., Canalizo, Gabriela, Filippenko, Alexei V., Gates, Elinor, Hamann, Frederick, Joner, Michael D., Malkan, Matthew A., Pancoast, Anna, Williams, Peter R., Woo, Jong-Hak, Abolfathi, Bela, Abramson, L. E., Armen, Stephen F., Bae, Hyun-Jin, and Bohn, Thomas
- Subjects
SEYFERT galaxies ,QUASARS ,ACTIVE galactic nuclei ,LIGHT curves ,BLACK holes ,SUPERMASSIVE black holes - Abstract
We carried out spectroscopic monitoring of 21 low-redshift Seyfert 1 galaxies using the Kast double spectrograph on the 3 m Shane telescope at Lick Observatory from 2016 April to 2017 May. Targeting active galactic nuclei (AGNs) with luminosities of λ L
λ (5100 Ă...) ≠1044 erg sâ'1 and predicted H β lags of âĽ20â€"30 days or black hole masses of 107 â€"108.5 M⊙ , our campaign probes luminosity-dependent trends in broad-line region (BLR) structure and dynamics as well as to improve calibrations for single-epoch estimates of quasar black hole masses. Here we present the first results from the campaign, including H β emission-line light curves, integrated H β lag times (8â€"30 days) measured against V -band continuum light curves, velocity-resolved reverberation lags, line widths of the broad H β components, and virial black hole mass estimates (107.1 â€"108.1 M⊙ ). Our results add significantly to the number of existing velocity-resolved lag measurements and reveal a diversity of BLR gas kinematics at moderately high AGN luminosities. AGN continuum luminosity appears not to be correlated with the type of kinematics that its BLR gas may exhibit. Follow-up direct modeling of this data set will elucidate the detailed kinematics and provide robust dynamical black hole masses for several objects in this sample. [ABSTRACT FROM AUTHOR]- Published
- 2022
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23. H α Reverberation Mapping of the Intermediate-mass Active Galactic Nucleus in NGC 4395.
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Cho, Hojin, Woo, Jong-Hak, Treu, Tommaso, Williams, Peter R., Armen, Stephen F., Barth, Aaron J., Bennert, Vardha N., Cho, Wanjin, Filippenko, Alexei V., Gallo, Elena, Geum, Jaehyuk, González-Buitrago, Diego, Gültekin, Kayhan, Hodges-Kluck, Edmund, Horst, John C., Hwang, Seong Hyeon, Kang, Wonseok, Kim, Minjin, Kim, Taewoo, and Leonard, Douglas C.
- Subjects
ACTIVE galactic nuclei ,LIGHT curves ,SPECTROSCOPIC imaging ,SPECTROGRAPHS ,BLACK holes ,SEYFERT galaxies ,GALACTIC nuclei - Abstract
We present the results of a high-cadence spectroscopic and imaging monitoring campaign of the active galactic nucleus (AGN) of NGC 4395. High signal-to-noise-ratio spectra were obtained at the Gemini-N 8 m telescope using the GMOS integral field spectrograph (IFS) on 2019 March 7 and at the Keck I 10 m telescope using the Low-Resolution Imaging Spectrometer with slit masks on 2019 March 3 and April 2. Photometric data were obtained with a number of 1 m-class telescopes during the same nights. The narrow-line region (NLR) is spatially resolved; therefore, its variable contributions to the slit spectra make the standard procedure of relative flux calibration impractical. We demonstrate that spatially resolved data from the IFS can be effectively used to correct the slit-mask spectral light curves. While we obtained no reliable lag owing to the lack of a strong variability pattern in the light curves, we constrain the broad-line time lag to be less than 3 hr, consistent with the photometric lag of âĽ80 minutes reported by Woo et al. By exploiting the high-quality spectra, we measure the second moment of the broad component of the H α emission line to be 586 ± 19 km s
â'1 , superseding the lower value reported by Woo et al. Combining the revised line dispersion and the photometric time lag, we update the black hole mass to (1.7 ± 0.3) Ă— 104 M⊙ . [ABSTRACT FROM AUTHOR]- Published
- 2021
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24. Discovery of a 310 Day Period from the Enshrouded Massive System NaSt1 (WR 122).
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Lau, Ryan M., Tinyanont, Samaporn, Hankins, Matthew J., Ashley, Michael C. B., De, Kishalay, Filippenko, Alexei V., Hillenbrand, Lynne A., Kasliwal, Mansi M., Mauerhan, Jon C., Moffat, Anthony F. J., Moore, Anna M., Smith, Nathan, Soon, Jamie, Soria, Roberto, Travouillon, Tony, van der Hucht, Karel A., Williams, Peredur M., and Zheng, WeiKang
- Subjects
LIGHT curves ,MASS transfer ,CIRCUMSTELLAR matter ,WOLF-Rayet stars ,SPECIAL effects in lighting ,SUPERGIANT stars - Abstract
We present optical and infrared (IR) light curves of NaSt1, also known as Wolfâ€"Rayet 122, with observations from Palomar Gattini-IR (PGIR), the Zwicky Transient Facility (ZTF), the Katzman Automatic Imaging Telescope, the Asteroid Terrestrial-impact Last Alert System, and the All-Sky Automated Survey for Supernovae (ASAS-SN). We identify a P = 309.7 ± 0.7 day photometric period from the optical and IR light curves that reveal periodic, sinusoidal variability between 2014 July and 2021 July. We also present historical IR light curves taken between 1983 July and 1989 May, which show variability consistent with the period of the present-day light curves. In the past, NaSt1 was brighter in the J band with larger variability amplitudes than the present-day PGIR values, suggesting that NaSt1 exhibits variability on longer (≳decade) timescales. Sinusoidal fits to the recent optical and IR light curves show that the amplitude of NaSt1's variability differs at various wavelengths and also reveal significant phase offsets of 17.0 ± 2.5 day between the ZTF r and PGIR J light curves. We interpret the 310 day photometric period from NaSt1 as the orbital period of an enshrouded massive binary. We suggest that the photometric variability of NaSt1 may arise from variations in the line-of-sight optical depth toward circumstellar optical/IR-emitting regions throughout its orbit due to colliding-wind dust formation. We speculate that past mass transfer in NaSt1 may have been triggered by Roche-lobe overflow (RLOF) during an eruptive phase of an Ofpe/WN9 star. Lastly, we argue that NaSt1 is no longer undergoing RLOF mass transfer. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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25. SN 2017fgc: A Fast-expanding Type Ia Supernova Exploded in Massive Shell Galaxy NGC 474.
- Author
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Zeng, Xiangyun, Wang, Xiaofeng, Esamdin, Ali, Pellegrino, Craig, Burke, Jamison, Stahl, Benjamin E., Zheng, WeiKang, Filippenko, Alexei V., Howell, D. Andrew, Sand, D. J., Valenti, Stefano, Mo, Jun, Xi, Gaobo, Liu, Jialian, Zhang, Jujia, Li, Wenxiong, Iskandar, Abdusamatjan, Zhang, Mengfan, Lin, Han, and Sai, Hanna
- Subjects
BIRTHPLACES ,VELOCITY ,LUMINOSITY - Abstract
We present extensive optical photometric and spectroscopic observations of the high-velocity (HV) Type Ia supernova (SN Ia) 2017fgc, covering the phase from ∼12 days before to ∼389 days after maximum brightness. SN 2017fgc is similar to normal SNe Ia, with an absolute peak magnitude of −19.32 ± 0.13 mag and a post-peak decline of Δm
15 (B) = 1.05 ± 0.07 mag. Its peak bolometric luminosity is derived as (1.32 ± 0.13) × 1043 erg s−1 , corresponding to a56 Ni mass of 0.51 ± 0.03 M⊙ . The light curves of SN 2017fgc are found to exhibit excess emission in the UBV bands in the early nebular phase and pronounced secondary shoulder/maximum features in the RrIi bands. Its spectral evolution is similar to that of HV SNe Ia, with a maximum-light Si ii velocity of 15,000 ± 150 km s−1 and a post-peak velocity gradient of ∼120 ± 10 km s−1 day−1 . The Fe ii and Mg ii lines blended near 4300 Å and the Fe ii , Si ii , and Fe iii lines blended near 4800 Å are obviously stronger than those of normal SNe Ia. Inspecting a large sample reveals that the strength of the two blends in the spectra, and the secondary peak in the i/r-band light curves, are found to be positively correlated with the maximum-light Si ii velocity. Such correlations indicate that HV SNe Ia may experience more complete burning in the ejecta and/or that their progenitors have higher metallicity. Examining the birthplace environment of SN 2017fgc suggests that it likely arose from a stellar environment with young and high-metallicity populations. [ABSTRACT FROM AUTHOR]- Published
- 2021
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26. Spitzer's Last Look at Extragalactic Explosions: Long-term Evolution of Interacting Supernovae.
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Szalai, Tamás, Fox, Ori D., Arendt, Richard G., Dwek, Eli, Andrews, Jennifer E., Clayton, Geoffrey C., Filippenko, Alexei V., Johansson, Joel, Kelly, Patrick L., Krafton, Kelsie, Marston, A. P., Mauerhan, Jon C., and Van Dyk, Schuyler D.
- Subjects
LONG-Term Evolution (Telecommunications) ,SUPERNOVAE ,SPACE telescopes ,EXPLOSIONS ,PHOTOMETRY ,CIRCUMSTELLAR matter - Abstract
Here we present new, yet final, mid-infrared (mid-IR) data for supernovae (SNe) based on measurements with the Spitzer Space Telescope. Comparing our recent 3.6 and 4.5 μm photometry with previously published mid-IR and further multiwavelength data sets, we were able to draw some conclusions about the origin and heating mechanism of the dust in these SNe or in their environments, as well as about possible connection with circumstellar matter (CSM) originating from pre-explosion mass-loss events in the progenitor stars. We also present new results regarding both certain SN classes and single objects. We highlight the mid-IR homogeneity of SNe Ia-CSM, which may be a hint of their common progenitor type and of their basically uniform circumstellar environments. Regarding single objects, it is worth highlighting the late-time interacting Type Ib SNe 2003gk and 2004dk, for which we present the first-ever mid-IR data, which seem to be consistent with clues of ongoing CSM interaction detected in other wavelength ranges. Our current study suggests that long-term mid-IR follow-up observations play a key role in a better understanding of both pre- and post-explosion processes in SNe and their environments. While Spitzer is not available anymore, the expected unique data from the James Webb Space Telescope, as well as long-term near-IR follow-up observations of dusty SNe, can bring us closer to the hidden details of this topic. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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27. ASASSN-14ms: The Most Energetic Known Explosion of a Type Ibn Supernova and Its Physical Origin.
- Author
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Wang, Xiaofeng, Lin, Weili, Zhang, Jujia, Zhang, Tianmeng, Cai, Yongzhi, Zhang, Kaicheng, Filippenko, Alexei V., Graham, Melissa, Maeda, Keiichi, Mo, Jun, Xiang, Danfeng, Xi, Gaobo, Yan, Shengyu, Wang, Lifan, Wang, Lingjun, Kawabata, Koji, and Zhai, Qian
- Subjects
LIGHT curves ,SUPERNOVAE ,EXPLOSIONS ,LUMINOSITY - Abstract
ASASSN-14ms may represent the most luminous Type Ibn supernova (SN Ibn) ever detected, with an absolute U-band magnitude brighter than −22.0 mag and a total bolometric luminosity >1.0 × 10
44 erg s−1 near maximum light. The early-time spectra of this SN are characterized by a blue continuum on which are superimposed narrow P Cygni profile lines of He i , suggesting the presence of slowly moving (∼1000 km s−1 ), He-rich circumstellar material (CSM). At 1–2 months after maximum brightness, the He i line profiles become only slightly broader, with blueshifted velocities of 2000–3000 km s−1 , consistent with the CSM shell being continuously accelerated by the SN light and ejecta. Like most SNe Ibn, the light curves of ASASSN-14ms show rapid post-peak evolution, dropping by ∼7 mag in the V band over three months. Such a rapid post-peak decline and high luminosity can be explained by interaction between SN ejecta and helium-rich CSM of 0.9 M⊙ at a distance of ∼1015 cm. The CSM around ASASSN-14ms is estimated to originate from a pre-explosion event with a mass-loss rate of 6.7 M⊙ yr−1 (assuming a velocity of ∼1000 km s−1 ), which is consistent with abundant He-rich material violently ejected during the late Wolf–Rayet (WN9-11 or Opfe) stage. After examining the light curves for a sample of SNe Ibn, we find that the more luminous ones tend to have slower post-peak decline rates, reflecting that the observed differences may arise primarily from discrepancies in the CSM distribution around the massive progenitors. [ABSTRACT FROM AUTHOR]- Published
- 2021
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28. The Blue Supergiant Progenitor of the Supernova Imposter AT 2019krl.
- Author
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Andrews, Jennifer E., Jencson, Jacob E., Van Dyk, Schuyler D., Smith, Nathan, Neustadt, Jack M. M., Sand, David J., Kreckel, K., Kochanek, C. S., Valenti, S., Strader, Jay, Bersten, M. C., Blanc, Guillermo A., Bostroem, K. Azalee, Brink, Thomas G., Emsellem, Eric, Filippenko, Alexei V., Folatelli, Gastón, Kasliwal, Mansi M., Masci, Frank J., and McElroy, Rebecca
- Subjects
SPACE telescopes ,STELLAR spectra ,SUPERNOVAE ,LIGHT curves ,SUPERGIANT stars ,TELESCOPES - Abstract
Extensive archival Hubble Space Telescope, Spitzer Space Telescope, and Large Binocular Telescope imaging of the recent intermediate-luminosity transient, AT 2019krl in M74, reveal a bright optical and mid-infrared progenitor star. While the optical peak of the event was missed, a peak was detected in the infrared with an absolute magnitude of M
4.5 μm = −18.4 mag, leading us to infer a visual-wavelength peak absolute magnitude of −13.5 to −14.5. The pre-discovery light curve indicated no outbursts over the previous 16 yr. The colors, magnitudes, and inferred temperatures of the progenitor best match a 13–14 M⊙ yellow or blue supergiant (BSG) if only foreground extinction is taken into account, or a hotter and more massive star if any additional local extinction is included. A pre-eruption spectrum of the star reveals strong Hα and [N ii ] emission with wings extending to ±2000 km s−1 . The post-eruption spectrum is fairly flat and featureless with only Hα, Na i D, [Ca ii ], and the Ca ii triplet in emission. As in many previous intermediate-luminosity transients, AT 2019krl shows remarkable observational similarities to luminous blue variable (LBV) giant eruptions, SN 2008S-like events, and massive-star mergers. However, the information about the pre-eruption star favors either a relatively unobscured BSG or a more extinguished LBV with M > 20 M⊙ likely viewed pole-on. [ABSTRACT FROM AUTHOR]- Published
- 2021
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29. Discovery of a Fast Iron Low-ionization Outflow in the Early Evolution of the Nearby Tidal Disruption Event AT 2019qiz.
- Author
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Hung, Tiara, Foley, Ryan J., Veilleux, S., Cenko, S. B., Dai, Jane L., Auchettl, Katie, Brink, Thomas G., Dimitriadis, Georgios, Filippenko, Alexei V., Gezari, S., Holoien, Thomas W.-S., Kilpatrick, Charles D., Mockler, Brenna, Piro, Anthony L., Ramirez-Ruiz, Enrico, Rojas-Bravo, César, Siebert, Matthew R., van Velzen, Sjoert, and Zheng, WeiKang
- Subjects
ACTIVE galactic nuclei ,INTERSTELLAR medium ,ATOMIC hydrogen ,SPACE telescopes ,INTERSTELLAR gases ,IRON ,SUPERNOVAE ,CORONAL mass ejections - Abstract
We report the results of ultraviolet (UV) and optical photometric and spectroscopic analysis of the tidal disruption event (TDE) AT 2019qiz. Our follow-up observations started <10 days after the source began to brighten in the optical and lasted for a period of six months. Our late-time host-dominated spectrum indicates that the host galaxy likely harbors a weak active galactic nucleus. The initial Hubble Space Telescope (HST) spectrum of AT 2019qiz exhibits an iron and low-ionization broad absorption line (FeLoBAL) system that is seen for the first time in a TDE. This spectrum also bears a striking resemblance to that of Gaia16apd, a superluminous supernova. Our observations provide insights into the outflow properties in TDEs and show evidence for a connection between TDEs and engine-powered supernovae at early phases, as originally suggested by Metzger & Stone. In a time frame of 50 days, the UV spectra of AT 2019qiz started to resemble those of previous TDEs with only high-ionization broad absorption lines. The change in UV spectral signatures is accompanied by a decrease in the outflow velocity, which began at 15,000 km s
−1 and decelerated to ∼10,000 km s−1 . A similar evolution in the Hα emission-line width further supports the speculation that the broad Balmer emission lines are formed in TDE outflows. In addition, we detect narrow absorption features on top of the FeLoBAL signatures in the early HST UV spectrum of AT 2019qiz. The measured H i column density corresponds to a Lyman-limit system, whereas the metal absorption lines (such as N v , C iv , Fe ii , and Mg ii) are likely probing the circumnuclear gas and interstellar medium in the host galaxy. [ABSTRACT FROM AUTHOR]- Published
- 2021
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30. The Palomar Transient Factory Core-collapse Supernova Host-galaxy Sample. I. Host-galaxy Distribution Functions and Environment Dependence of Core-collapse Supernovae.
- Author
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Schulze, Steve, Yaron, Ofer, Sollerman, Jesper, Leloudas, Giorgos, Gal, Amit, Wright, Angus H., Lunnan, Ragnhild, Gal-Yam, Avishay, Ofek, Eran O., Perley, Daniel A., Filippenko, Alexei V., Kasliwal, Mansi M., Kulkarni, Shrinivas R., Neill, James D., Nugent, Peter E., Quimby, Robert M., Sullivan, Mark, Strotjohann, Nora Linn, Arcavi, Iair, and Ben-Ami, Sagi
- Published
- 2021
- Full Text
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31. Bright, Months-long Stellar Outbursts Announce the Explosion of Interaction-powered Supernovae.
- Author
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Strotjohann, Nora L., Ofek, Eran O., Gal-Yam, Avishay, Bruch, Rachel, Schulze, Steve, Shaviv, Nir, Sollerman, Jesper, Filippenko, Alexei V., Yaron, Ofer, Fremling, Christoffer, Nordin, Jakob, Kool, Erik C., Perley, Dan A., Ho, Anna Y. Q., Yang, Yi, Yao, Yuhan, Soumagnac, Maayane T., Graham, Melissa L., Barbarino, Cristina, and Tartaglia, Leonardo
- Subjects
SUPERNOVAE ,LIGHT curves ,RADIATION ,EXPLOSIONS - Abstract
Interaction-powered supernovae (SNe) explode within an optically thick circumstellar medium (CSM) that could be ejected during eruptive events. To identify and characterize such pre-explosion outbursts, we produce forced-photometry light curves for 196 interacting SNe, mostly of Type IIn, detected by the Zwicky Transient Facility between early 2018 and 2020 June. Extensive tests demonstrate that we only expect a few false detections among the 70,000 analyzed pre-explosion images after applying quality cuts and bias corrections. We detect precursor eruptions prior to 18 Type IIn SNe and prior to the Type Ibn SN 2019uo. Precursors become brighter and more frequent in the last months before the SN and month-long outbursts brighter than magnitude −13 occur prior to 25% (5–69%, 95% confidence range) of all Type IIn SNe within the final three months before the explosion. With radiative energies of up to 10
49 erg, precursors could eject ∼1 M⊙ of material. Nevertheless, SNe with detected precursors are not significantly more luminous than other SNe IIn, and the characteristic narrow hydrogen lines in their spectra typically originate from earlier, undetected mass-loss events. The long precursor durations require ongoing energy injection, and they could, for example, be powered by interaction or by a continuum-driven wind. Instabilities during the neon- and oxygen-burning phases are predicted to launch precursors in the final years to months before the explosion; however, the brightest precursor is 100 times more energetic than anticipated. [ABSTRACT FROM AUTHOR]- Published
- 2021
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32. The Zwicky Transient Facility Bright Transient Survey. II. A Public Statistical Sample for Exploring Supernova Demographics.
- Author
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Perley, Daniel A., Fremling, Christoffer, Sollerman, Jesper, Miller, Adam A., Dahiwale, Aishwarya S., Sharma, Yashvi, Bellm, Eric C., Biswas, Rahul, Brink, Thomas G., Bruch, Rachel J., De, Kishalay, Dekany, Richard, Drake, Andrew J., Duev, Dmitry A., Filippenko, Alexei V., Gal-Yam, Avishay, Goobar, Ariel, Graham, Matthew J., Graham, Melissa L., and Ho, Anna Y. Q.
- Subjects
STATISTICAL sampling ,DEMOGRAPHIC surveys ,OPTICAL limiting ,SUPERNOVAE ,STELLAR luminosity function ,LUMINOSITY - Abstract
We present a public catalog of transients from the Zwicky Transient Facility (ZTF) Bright Transient Survey, a magnitude-limited (m < 19 mag in either the g or r filter) survey for extragalactic transients in the ZTF public stream. We introduce cuts on survey coverage, sky visibility around peak light, and other properties unconnected to the nature of the transient, and show that the resulting statistical sample is spectroscopically 97% complete at <18 mag, 93% complete at <18.5 mag, and 75% complete at <19 mag. We summarize the fundamental properties of this population, identifying distinct duration–luminosity correlations in a variety of supernova (SN) classes and associating the majority of fast optical transients with well-established spectroscopic SN types (primarily SN Ibn and II/IIb). We measure the Type Ia SN and core-collapse (CC) SN rates and luminosity functions, which show good consistency with recent work. About 7% of CC SNe explode in very low-luminosity galaxies (M
i > −16 mag), 10% in red-sequence galaxies, and 1% in massive ellipticals. We find no significant difference in the luminosity or color distributions between the host galaxies of SNe Type II and SNe Type Ib/c, suggesting that line-driven wind stripping does not play a major role in the loss of the hydrogen envelope from their progenitors. Future large-scale classification efforts with ZTF and other wide-area surveys will provide high-quality measurements of the rates, properties, and environments of all known types of optical transients and limits on the existence of theoretically predicted but as yet unobserved explosions. [ABSTRACT FROM AUTHOR]- Published
- 2020
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33. Heated Poles on the Companion of Redback PSR J2339–0533.
- Author
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Kandel, D., Romani, Roger W., Filippenko, Alexei V., Brink, Thomas G., and Zheng, WeiKang
- Subjects
OPTICAL measurements ,GAMMA ray bursts ,NEUTRON stars ,BINARY pulsars ,MAGNETIC pole - Abstract
We analyze the photometry and spectra of the "redback" millisecond pulsar binary J2339−0533. These observations include new measurements from Keck and the Gamma-Ray Burst Optical/Near-infrared Detector (GROND), as well as archival measurements from the Optical and Infrared Synergetic Telescopes for Education and Research (OISTER), WIYN, Southern Astrophysical Research (SOAR), and Hobby–Eberly Telescope (HET) telescopes. The parameters derived from GROND, our primary photometric data, describe well the rest of the data sets, raising our confidence in our fitted binary properties. Our fit requires hot spots (likely magnetic poles) on the surface of the companion star, and we see evidence that these spots move over the 8 yr span of our photometry. The derived binary inclination i = 69.°3 ± 2.°3, together with the center-of-mass velocity (from the radial-velocity fits) K
C = 347.0 ± 3.7 , give a fairly typical neutron star mass of 1.47 ± 0.09 M⊙ . [ABSTRACT FROM AUTHOR]- Published
- 2020
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- View/download PDF
34. A Measurement of the Hubble Constant Using Gravitational Waves from the Binary Merger GW190814.
- Author
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Vasylyev, Sergiy S. and Filippenko, Alexei V.
- Subjects
- *
GRAVITATIONAL constant , *GRAVITATIONAL waves , *LASER interferometers , *HUBBLE constant , *NEUTRON stars , *TEST methods , *BINARY stars - Abstract
We present a test of the statistical method introduced by Bernard F. Shutz in 1986 using only gravitational waves to infer the Hubble constant (H0) from GW190814, the first high-probability neutron-star–black hole (NS–BH) merger candidate detected by the Laser Interferometer gravitational-wave Observatory (LIGO) and the Virgo interferometer. We apply a baseline test of this method to the binary neutron star (BNS) merger GW170817 and find km s−1 Mpc−1 (maximum a posteriori and 68.3% highest density posterior interval) for a galaxy B-band luminosity threshold of with a correction for catalog incompleteness. Repeating the calculation for GW190814, we obtain km s−1 Mpc−1 and km s−1 Mpc−1 for and , respectively. Combining the posteriors for both events yields km s−1 Mpc−1, demonstrating the improvement on constraints when using multiple gravitational-wave events. We also confirm the results of other works that adopt this method, showing that increasing the LB threshold enhances the posterior structure and slightly shifts the distribution's peak to higher H0 values.We repeat the joint inference using the low-spin PhenomPNRT and the newly available combined (SEOBNRv4PHM + IMRPhenomPv3HM) posterior samples for GW170817 and GW190814, respectively, achieving a tighter constraint of km s−1 Mpc−1. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
35. GRB 140423A: A Case of Stellar Wind to Interstellar Medium Transition in the Afterglow.
- Author
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Li, Long, Wang, Xiang-Gao, Zheng, WeiKang, Pozanenko, Alexei S., Filippenko, Alexei V., Qin, Songmei, Wang, Shan-Qin, Jiang, Lu-Yao, Li, Jing, Lin, Da-Bin, Liang, En-Wei, Volnova, Alina A., Elenin, Leonid, Klunko, Evgeny, Inasaridze, Raguli Ya., Kusakin, Anatoly, and Lu, Rui-Jing
- Subjects
MONTE Carlo method ,GAMMA ray bursts ,STELLAR winds ,INTERSTELLAR medium ,SPECTRAL energy distribution ,OPTICAL telescopes ,LIGHT curves - Abstract
We present very early ground-based optical follow-up observations of gamma-ray burst (GRB) 140423A, which was discovered by the Swift/Burst Alert Telescope (BAT) and by the Fermi/Gamma-Ray Burst Monitor. Its broadband afterglow was monitored by the Swift/X-Ray Telescope and ground-based optical telescopes from T
0 + 70.96 s to 4.8 days after the Swift/BAT trigger. This is one more case of a prompt optical emission observation. The temporal and spectral joint fits of the multiwavelength light curves of GRB 140423A reveal that achromatic behavior is consistent with the external shock model, including a transition from a stellar wind to the interstellar medium (ISM) and energy injection. In terms of the optical light curves, there is an onset bump in the early afterglow with a rising index (peaking at s). It then decays with a steep index , and shows a steeper to flatter "transition" with at around T0 + 5000 s. The observed X-ray afterglow reflects achromatic behavior, as does the optical light curve. There is no obvious evolution of the spectral energy distribution between the X-ray and optical afterglows, with an average value of the photon index. This "transition" is consistent with an external shock model having the circumburst medium transition from a wind to the ISM, by introducing a long-lasting energy injection with a Lorentz factor stratification of the ejecta. The best parameters from Monte Carlo Markov Chain fitting are erg, , , , , cm, , , , , and. [ABSTRACT FROM AUTHOR]- Published
- 2020
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36. Early Optical Observations of GRB 150910A: Bright Jet Optical Afterglow and X-Ray Dipole Radiation from a Magnetar Central Engine.
- Author
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Xie, Lang, Wang, Xiang-Gao, Zheng, WeiKang, Filippenko, Alexei V., Qin, Song-Mei, Li, Long, Zheng, Tian-Ci, Zou, Le, Lin, Da-Bin, Zhu, Yinan, Yuk, Heechan, Lu, Rui-Jing, and Liang, En-Wei
- Subjects
GAMMA ray bursts ,MAGNETIC flux density ,X-rays ,ECHOLOCATION (Physiology) ,RADIATION ,LIGHT curves ,MAGNETIC dipoles - Abstract
Gamma-ray burst (GRB) 150910A was detected by Swift/Burst Alert Telescope (BAT), and then rapidly observed by Swift/XRT, Swift/Ultraviolet-Optical Telescope, and ground-based telescopes. We report Lick Observatory spectroscopic and photometric observations of GRB 150910A, and we investigate the physical origins of both the optical and X-ray afterglows, incorporating data obtained with BAT and XRT. The light curves show that the jet-emission episode lasts ∼360 s with a sharp pulse from BAT to XRT (Episode I). In Episode II, the optical emission has a smooth onset bump followed by a normal decay (α
R,2 ≈ −1.36), as predicted in the standard external shock model, while the X-ray emission exhibits a plateau (αX,1 ≈ −0.36) followed by a steep decay (αX,2 ≈ −2.12). The light curves show obvious chromatic behavior with an excess in the X-ray flux. Our results suggest that GRB 150910A is an unusual GRB driven by a newly born magnetar with its extremely energetic magnetic dipole (MD) wind in Episode II, which overwhelmingly dominates the observed early X-ray plateau. The radiative efficiency of the jet prompt emission is ηγ ≈ 11%. The MD wind emission was detected in both the BAT and XRT bands, making it the brightest among the current sample of MD winds seen by XRT. We infer the initial spin period (P0 ) and the surface polar cap magnetic field strength (Bp ) of the magnetar as 1.02 × 1015 G ≤ Bp ≤ 1.80 × 1015 G and 1 ms ≤ P0 v ≤ 1.77 ms, and the radiative efficiency of the wind is ηw ≥ 32%. [ABSTRACT FROM AUTHOR]- Published
- 2020
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37. The Data Release of the Sloan Digital Sky Survey-II Supernova Survey
- Author
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Sako, Masao, primary, Bassett, Bruce, additional, Becker, Andrew C., additional, Brown, Peter J., additional, Campbell, Heather, additional, Wolf, Rachel, additional, Cinabro, David, additional, D’Andrea, Chris B., additional, Dawson, Kyle S., additional, DeJongh, Fritz, additional, Depoy, Darren L., additional, Dilday, Ben, additional, Doi, Mamoru, additional, Filippenko, Alexei V., additional, Fischer, John A., additional, Foley, Ryan J., additional, Frieman, Joshua A., additional, Galbany, Lluis, additional, Garnavich, Peter M., additional, Goobar, Ariel, additional, Gupta, Ravi R., additional, Hill, Gary J., additional, Hayden, Brian T., additional, Hlozek, Renée, additional, Holtzman, Jon A., additional, Hopp, Ulrich, additional, Jha, Saurabh W., additional, Kessler, Richard, additional, Kollatschny, Wolfram, additional, Leloudas, Giorgos, additional, Marriner, John, additional, Marshall, Jennifer L., additional, Miquel, Ramon, additional, Morokuma, Tomoki, additional, Mosher, Jennifer, additional, Nichol, Robert C., additional, Nordin, Jakob, additional, Olmstead, Matthew D., additional, Östman, Linda, additional, Prieto, Jose L., additional, Richmond, Michael, additional, Romani, Roger W., additional, Sollerman, Jesper, additional, Stritzinger, Max, additional, Schneider, Donald P., additional, Smith, Mathew, additional, Wheeler, J. Craig, additional, Yasuda, Naoki, additional, and Zheng, Chen, additional
- Published
- 2018
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38. Revisiting the Lick Observatory Supernova Search Volume-limited Sample: Updated Classifications and Revised Stripped-envelope Supernova Fractions
- Author
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Shivvers, Isaac, primary, Modjaz, Maryam, additional, Zheng, WeiKang, additional, Liu, Yuqian, additional, Filippenko, Alexei V., additional, Silverman, Jeffrey M., additional, Matheson, Thomas, additional, Pastorello, Andrea, additional, Graur, Or, additional, Foley, Ryan J., additional, Chornock, Ryan, additional, Smith, Nathan, additional, Leaman, Jesse, additional, and Benetti, Stefano, additional
- Published
- 2017
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39. Modeling the Light Curves of the Luminous Type Ic Supernova 2007D.
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Wang, Shan-Qin, Cano, Zach, Li, Long, Liu, Liang-Duan, Wang, Ling-Jun, Zheng, WeiKang, Dai, Zi-Gao, Liang, En-Wei, and Filippenko, Alexei V.
- Subjects
TYPE I supernovae ,LIGHT curves ,MAGNETARS ,MAGNETIC flux density - Abstract
SN 2007D is a nearby (redshift z = 0.023146), luminous Type Ic supernova (SN) having a narrow light curve (LC) and high peak luminosity. Previous research based on the assumption that it was powered by the
56 Ni cascade decay suggested that the inferred56 Ni mass and the ejecta mass are ∼1.5 M⊙ and ∼3.5 M⊙ , respectively. In this paper, we employ some multiband LC models to model the R-band LC and the color (V − R) evolution of SN 2007D to investigate the possible energy sources powering them. We find that the pure56 Ni model is disfavored; the multiband LCs of SN 2007D can be reproduced by a magnetar whose initial rotational period P0 and magnetic field strength Bp are (or) ms and (or) G, respectively. By comparing the spectrum of SN 2007D with that of some superluminous SNe (SLSNe), we find that it might be a luminous SN like several luminous "gap-filler" optical transients that bridge ordinary and SLSNe, rather than a genuine SLSN. [ABSTRACT FROM AUTHOR]- Published
- 2019
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40. Optical Identification of Cepheids in 19 Host Galaxies of Type Ia Supernovae and NGC 4258 with the hubble space telescope
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Hoffmann, Samantha L., Macri, Lucas M., Riess, Adam, Yuan, Wenlong, Casertano, Stefano, Foley, Ryan, Filippenko, Alexei V., Tucker , Bradley, Chornock, Ryan, Silverman, J M, Welch, D L, Goobar, Ariel, Amanullah, Rahman, Hoffmann, Samantha L., Macri, Lucas M., Riess, Adam, Yuan, Wenlong, Casertano, Stefano, Foley, Ryan, Filippenko, Alexei V., Tucker , Bradley, Chornock, Ryan, Silverman, J M, Welch, D L, Goobar, Ariel, and Amanullah, Rahman
- Abstract
We present results of an optical search conducted as part of the SH0ES project (Supernovae and H0 for the Equation of State of dark energy) for Cepheid variable stars using the Hubble Space Telescope (HST) in 19 hosts of Type Ia supernovae (SNe Ia) and the maser-host galaxy NGC 4258. The targets include nine newly imaged SN Ia hosts using a novel strategy based on a long-pass filter that minimizes the number of HST orbits required to detect and accurately determine Cepheid properties. We carried out a homogeneous reduction and analysis of all observations, including new universal variability searches in all SN Ia hosts, which yielded a total of 2200 variables with well-defined selection criteria, the largest such sample identified outside the Local Group. These objects are used in a companion paper to determine the local value of H0 with a total uncertainty of 2.4%.
- Published
- 2016
41. The Palomar Transient Factory: System Overview, Performance, and First Results
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Law, Nicholas M., primary, Kulkarni, Shrinivas R., additional, Dekany, Richard G., additional, Ofek, Eran O., additional, Quimby, Robert M., additional, Nugent, Peter E., additional, Surace, Jason, additional, Grillmair, Carl C., additional, Bloom, Joshua S., additional, Kasliwal, Mansi M., additional, Bildsten, Lars, additional, Brown, Tim, additional, Cenko, S. Bradley, additional, Ciardi, David, additional, Croner, Ernest, additional, Djorgovski, S. George, additional, van Eyken, Julian, additional, Filippenko, Alexei V., additional, Fox, Derek B., additional, Gal-Yam, Avishay, additional, Hale, David, additional, Hamam, Nouhad, additional, Helou, George, additional, Henning, John, additional, Howell, D. Andrew, additional, Jacobsen, Janet, additional, Laher, Russ, additional, Mattingly, Sean, additional, McKenna, Dan, additional, Pickles, Andrew, additional, Poznanski, Dovi, additional, Rahmer, Gustavo, additional, Rau, Arne, additional, Rosing, Wayne, additional, Shara, Michael, additional, Smith, Roger, additional, Starr, Dan, additional, Sullivan, Mark, additional, Velur, Viswa, additional, Walters, Richard, additional, and Zolkower, Jeff, additional
- Published
- 2009
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42. Exploring the Optical Transient Sky with the Palomar Transient Factory
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Rau, Arne, primary, Kulkarni, Shrinivas R., additional, Law, Nicholas M., additional, Bloom, Joshua S., additional, Ciardi, David, additional, Djorgovski, George S., additional, Fox, Derek B., additional, Gal-Yam, Avishay, additional, Grillmair, Carl C., additional, Kasliwal, Mansi M., additional, Nugent, Peter E., additional, Ofek, Eran O., additional, Quimby, Robert M., additional, Reach, William T., additional, Shara, Michael, additional, Bildsten, Lars, additional, Cenko, S. Bradley, additional, Drake, Andrew J., additional, Filippenko, Alexei V., additional, Helfand, David J., additional, Helou, George, additional, Howell, D. Andrew, additional, Poznanski, Dovi, additional, and Sullivan, Mark, additional
- Published
- 2009
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43. Optical Spectroscopy of the Somewhat Peculiar Type IIb Supernova 2001ig
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Silverman, Jeffrey M., primary, Mazzali, Paolo, additional, Chornock, Ryan, additional, Filippenko, Alexei V., additional, Clocchiatti, Alejandro, additional, Phillips, Mark M., additional, Ganeshalingam, Mohan, additional, and Foley, Ryan J., additional
- Published
- 2009
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44. Late-TimeHSTPhotometry of SN 1994I: Hints of Positron Annihilation Energy Deposition
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Clocchiatti, Alejandro, primary, Wheeler, J. Craig, additional, Kirshner, Robert P., additional, Branch, David, additional, Challis, Peter, additional, Chevalier, Roger A., additional, Filippenko, Alexei V., additional, Fransson, Claes, additional, Garnavich, Peter, additional, Leibundgut, Bruno, additional, Panagia, Nino, additional, Phillips, Mark M., additional, Suntzeff, Nicholas B., additional, Höflich, Peter A., additional, and Gallardo, José, additional
- Published
- 2008
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45. Keck Spectroscopy ofROSATUltraluminous X-Ray Source Candidates
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Wong, Diane S., primary, Chornock, Ryan, additional, and Filippenko, Alexei V., additional
- Published
- 2008
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46. The Peculiar SN 2005hk: Do Some Type Ia Supernovae Explode as Deflagrations?
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Phillips, M. M., primary, Li, Weidong, additional, Frieman, Joshua A., additional, Blinnikov, S. I., additional, DePoy, Darren, additional, Prieto, José L., additional, Milne, P., additional, Contreras, Carlos, additional, Folatelli, Gastón, additional, Morrell, Nidia, additional, Hamuy, Mario, additional, Suntzeff, Nicholas B., additional, Roth, Miguel, additional, González, Sergio, additional, Krzeminski, Wojtek, additional, Filippenko, Alexei V., additional, Freedman, Wendy L., additional, Chornock, Ryan, additional, Jha, Saurabh, additional, Madore, Barry F., additional, Persson, S. E., additional, Burns, Christopher R., additional, Wyatt, Pamela, additional, Murphy, David, additional, Foley, Ryan J., additional, Ganeshalingam, Mohan, additional, Serduke, Franklin J. D., additional, Krisciunas, Kevin, additional, Bassett, Bruce, additional, Becker, Andrew, additional, Dilday, Ben, additional, Eastman, J., additional, Garnavich, Peter M., additional, Holtzman, Jon, additional, Kessler, Richard, additional, Lampeitl, Hubert, additional, Marriner, John, additional, Frank, S., additional, Marshall, J. L., additional, Miknaitis, Gajus, additional, Sako, Masao, additional, Schneider, Donald P., additional, van der Heyden, Kurt, additional, and Yasuda, Naoki, additional
- Published
- 2007
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47. Direct Analysis of Spectra of the Unusual Type Ib Supernova 2005bf
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Parrent, Jerod, primary, Branch, David, additional, Troxel, M. A., additional, Casebeer, D., additional, Jeffery, David J., additional, Ketchum, W., additional, Baron, E., additional, Serduke, F. J. D., additional, and Filippenko, Alexei V., additional
- Published
- 2007
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48. Spectropolarimetry of the Peculiar Type Ia Supernova 2005hk
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Chornock, Ryan, primary, Filippenko, Alexei V., additional, Branch, David, additional, Foley, Ryan J., additional, Jha, Saurabh, additional, and Li, Weidong, additional
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- 2006
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49. The Light Echo around Supernova 2003gd in Messier 74
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Van Dyk, Schuyler D., primary, Li, Weidong, additional, and Filippenko, Alexei V., additional
- Published
- 2006
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50. The Carnegie Supernova Project: The Low‐Redshift Survey
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Hamuy, Mario, primary, Folatelli, Gastón, additional, Morrell, Nidia I., additional, Phillips, Mark M., additional, Suntzeff, Nicholas B., additional, Persson, S. E., additional, Roth, Miguel, additional, Gonzalez, Sergio, additional, Krzeminski, Wojtek, additional, Contreras, Carlos, additional, Freedman, Wendy L., additional, Murphy, D. C., additional, Madore, Barry F., additional, Wyatt, P., additional, Maza, José, additional, Filippenko, Alexei V., additional, Li, Weidong, additional, and Pinto, P. A., additional
- Published
- 2006
- Full Text
- View/download PDF
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