Browsing by Author "Filippenko, A. V."

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    Final Moments. II. Observational Properties and Physical Modeling of Circumstellar-material-interacting Type II Supernovae
    (2024) Jacobson-Galan, W. V.; Dessart, L.; Davis, K. W.; Kilpatrick, C. D.; Margutti, R.; Foley, R. J.; Chornock, R.; Terreran, G.; Hiramatsu, D.; Newsome, M.; Padilla Gonzalez, E.; Pellegrino, C.; Howell, D. A.; Filippenko, A. V.; Anderson, J. P.; Angus, C. R.; Auchettl, K.; Bostroem, K. A.; Brink, T. G.; Cartier, R.; Coulter, D. A.; de Boer, T.; Drout, M. R.; Earl, N.; Ertini, K.; Farah, J. R.; Farias, D.; Gall, C.; Gao, H.; Gerlach, M. A.; Guo, F.; Haynie, A.; Hosseinzadeh, G.; Ibik, A. L.; Jha, S. W.; Jones, D. O.; Langeroodi, D.; Lebaron, N.; Magnier, E. A.; Piro, A. L.; Raimundo, S. I.; Rest, A.; Rest, S.; Rich, R. Michael; Rojas-Bravo, C.; Sears, H.; Taggart, K.; Villar, V. A.; Wainscoat, R. J.; Wang, X-f.; Wasserman, A. R.; Yan, S.; Yang, Y.; Zhang, J.; Zheng, W.
    We present ultraviolet/optical/near-infrared observations and modeling of Type II supernovae (SNe II) whose early time (delta(t) < 2 days) spectra show transient, narrow emission lines from shock ionization of confined (r < 10(15) cm) circumstellar material (CSM). The observed electron-scattering broadened line profiles (i.e., IIn-like) of H i, He i/ii, C iv, and N iii/iv/v from the CSM persist on a characteristic timescale (t(IIn)) that marks a transition to a lower-density CSM and the emergence of Doppler-broadened features from the fast-moving SN ejecta. Our sample, the largest to date, consists of 39 SNe with early time IIn-like features in addition to 35 "comparison" SNe with no evidence of early time IIn-like features, all with ultraviolet observations. The total sample includes 50 unpublished objects with a total of 474 previously unpublished spectra and 50 multiband light curves, collected primarily through the Young Supernova Experiment and Global Supernova Project collaborations. For all sample objects, we find a significant correlation between peak ultraviolet brightness and both t(II)n and the rise time, as well as evidence for enhanced peak luminosities in SNe II with IIn-like features. We quantify mass-loss rates and CSM density for the sample through the matching of peak multiband absolute magnitudes, rise times, t(IIn), and optical SN spectra with a grid of radiation hydrodynamics and non-local thermodynamic equilibrium radiative-transfer simulations. For our grid of models, all with the same underlying explosion, there is a trend between the duration of the electron-scattering broadened line profiles and inferred mass-loss rate: t(IIn) approximate to 3.8[M/ (0.01 M-circle dot yr(-1))] days.
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    First Cosmology Results using Supernovae Ia from the Dark Energy Survey : Survey Overview, Performance, and Supernova Spectroscopy
    (2020) Smith, M.; D'Andrea, C. B.; Sullivan, M.; Moller, A.; Nichol, R. C.; Thomas, R. C.; Kim, A. G.; Sako, M.; Castander, F. J.; Clocchiatti, Alejandro; Filippenko, A. V.; Foley, R. J.; Galbany, L.; González Gaitan, S.; Kasai, E.; Kirshner, R. P.; Lidman, C.; Scolnic, D.; Brout, D.; Davis, T. M.; Gupta, R. R.; Hinton, S. R.; Kessler, R.; Lasker, J.; Macaulay, E.; Wolf, R. C.; Zhang, B.; Asorey, J.; Avelino, A.; Bassett, B. A.; Calcino, J.; Carollo, D.; Casas, R.; Challis, P.; Childress, M.; Crawford, S.; Frohmaier, C.; Glazebrook, K.; Goldstein, D. A.; Graham, M. L.; Hoormann, J. K.; Kuehn, K.; Lewis, G. F.; Mandel, K. S.; Morganson, E.; Muthukrishna, D.; Nugent, P.; Pan, Y. C.; Pursiainen, M.; Sharp, R.
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    First cosmology results using Type Ia supernova from the Dark Energy Survey: simulations to correct supernova distance biases
    (2019) Kessler, R.; Brout, D.; D'Andrea, C. B.; Davis, T. M.; Hinton, S. R.; Kim, A. G.; Lasker, J.; Lidman, C.; Macaulay, E.; Moeller, A.; Sako, M.; Scolnic, D.; Smith, M.; Sullivan, M.; Zhang, B.; Andersen, P.; Asorey, J.; Avelino, A.; Calcino, J.; Carollo, D.; Challis, P.; Childress, M.; Clocchiatti, A.; Crawford, S.; Filippenko, A. V.; Foley, R. J.; Glazebrook, K.; Hoormann, J. K.; Kasai, E.; Kirshner, R. P.; Lewis, G. F.; Mandel, K. S.; March, M.; Morganson, E.; Muthukrishna, D.; Nugent, P.; Pan, Y. -C.; Sommer, N. E.; Swann, E.; Thomas, R. C.; Tucker, B. E.; Uddin, S. A.; Abbott, T. M. C.; Allam, S.; Annis, J.; Avila, S.; Banerji, M.; Bechtol, K.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Crocce, M.; da Costa, L. N.; Davis, C.; De Vicente, J.; Desai, S.; Diehl, H. T.; Doel, P.; Eifler, T. F.; Flaugher, B.; Fosalba, P.; Frieman, J.; Garcia-Bellido, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Hartley, W. G.; Hollowood, D. L.; Honscheid, K.; James, D. J.; Johnson, M. W. G.; Johnson, M. D.; Krause, E.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Menanteau, F.; Miller, C. J.; Miquel, R.; Nord, B.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Serrano, S.; Sevilla-Noarbe, I.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Walker, A. R.; Zhang, Y.
    We describe catalogue-level simulations of Type Ia supernova (SN Ia) light curves in the Dark Energy Survey Supernova Program (DES-SN) and in low-redshift samples from the Center for Astrophysics (CfA) and the Carnegie Supernova Project (CSP). These simulations are used to model biases from selection effects and light-curve analysis and to determine bias corrections for SN Ia distance moduli that are used to measure cosmological parameters. To generate realistic light curves, the simulation uses a detailed SN Ia model, incorporates information from observations (point spread function, sky noise, zero-point), and uses summary information (e.g. detection efficiency versus signal-to-noise ratio) based on 10 000 fake SN light curves whose fluxes were overlaid on images and processed with our analysis pipelines. The quality of the simulation is illustrated by predicting distributions observed in the data. Averaging within redshift bins, we find distance modulus biases up to 0.05 mag over the redshift ranges of the low-z and DES-SN samples. For individual events, particularly those with extreme red or blue colour, distance biases can reach 0.4 mag. Therefore, accurately determining bias corrections is critical for precision measurements of cosmological parameters. Files used to make these corrections are available at https://des.ncsa.illinois.edu/releases/sn.
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    SN 2004aw
    (2006) Taubenberger, S.; Pastorello, A.; Mazzali, P. A.; Valenti, S.; Pignata, G.; Sauer, D. N.; Arbey, A.; Baernbantner, O.; Benetti, S.; Della Valle, A.; Deng, J.; Elias-Rosa, N.; Filippenko, A. V.; Foley, R. J.; Goobar, A.; Kotak, R.; Li, W.; Meikle, P.; Mendez, J.; Patat, F.; Pian, E.; Ries, C.; Ruiz-Lapuente, P.; Salvo, M.; Stanishev, V.; Turatto, M.; Hillebrandt, W.
    Optical and near-infrared (near-IR) observations of the Type Ic supernova (SN Ic) 2004aw are presented, obtained from -3 to +413 d with respect to the B-band maximum. The photometric evolution is characterized by a comparatively slow post-maximum decline of the light curves. The peaks in redder bands are significantly delayed relative to the bluer bands, the I-band maximum occurring 8.4 d later than that in B. With an absolute peak magnitude of -18.02 in the V band the SN can be considered fairly bright, but not exceptional. This also holds for the U through I bolometric light curve, where SN 2004aw has a position intermediate between SNe 2002ap and 1998bw. Spectroscopically SN 2004aw provides a link between a normal SN Ic like SN 1994I and the group of broad-lined SNe Ic. The spectral evolution is rather slow, with a spectrum at day +64 being still predominantly photospheric. The shape of the nebular [O-I] lambda lambda 6300, 6364 line indicates a highly aspherical explosion. Helium cannot be unambiguously identified in the spectra, even in the near-IR. Using an analytical description of the light-curve peak we find that the total mass of the ejecta in SN 2004aw is 3.5-8.0 M-circle dot, significantly larger than that in SN 1994I, although not as large as in SN 1998bw. The same model suggests that about 0.3 M-circle dot of Ni-56 has been synthesized in the explosion. No connection to a GRB can be firmly established.
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    Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548
    (IOP PUBLISHING LTD, 2017) Pei, L.; Fausnaugh, M. M.; Barth, A. J.; Peterson, B. M.; Bentz, M. C.; De Rosa, G.; Denney, K. D.; Goad, M. R.; Kochanek, C. S.; Korista, K. T.; Kriss, G. A.; Pogge, R. W.; Bennert, V. N.; Brotherton, M.; Clubb, K. I.; Dalla Bonta, E.; Filippenko, A. V.; Greene, J. E.; Grier, C. J.; Vestergaard, M.; Zheng, W.; Adams, Scott M.; Beatty, Thomas G.; Bigley, A.; Brown, Jacob E.; Brown, Jonathan S.; Canalizo, G.; Comerford, J. M.; Coker, Carl T.; Corsini, E. M.; Croft, S.; Croxall, K. V.; Deason, A. J.; Eracleous, Michael; Fox, O. D.; Gates, E. L.; Henderson, C. B.; Holmbeck, E.; Holoien, T. W. S.; Jensen, J. J.; Johnson, C. A.; Kelly, P. L.; Kim, S.; King, A.; Lau, M. W.; Li, Miao; Lochhaas, Cassandra; Ma, Zhiyuan; Manne Nicholas, E. R.; Mauerhan, J. C.; Malkan, M. A.; McGurk, R.; Morelli, L.; Mosquera, Ana; Mudd, Dale; Sanchez, F. Muller; Nguyen, M. L.; Ochner, P.; Ou Yang, B.; Pancoast, A.; Penny, Matthew T.; Pizzella, A.; Poleski, Radoslaw; Runnoe, Jessie; Scott, B.; Schimoia, Jaderson S.; Shappee, B. J.; Shivvers, I.; Simonian, Gregory V.; Siviero, A.; Somers, Garrett; Stevens, Daniel J.; Strauss, M. A.; Tayar, Jamie; Tejos, N.; Treu, T.; Van Saders, J.; Vican, L.; Villanueva, S., Jr.; Yuk, H.; Zakamska, N. L.; Zhu, W.; Anderson, M. D.; Arevalo, P.; Bazhaw, C.; Bisogni, S.; Borman, G. A.; Bottorff, M. C.; Brandt, W. N.; Breeveld, A. A.; Cackett, E. M.; Carini, M. T.; Crenshaw, D. M.; De Lorenzo Caceres, A.; Dietrich, M.; Edelson, R.; Efimova, N. V.; Ely, J.; Evans, P. A.; Ferland, G. J.; Flatland, K.; Gehrels, N.; Geier, S.; Gelbord, J. M.; Grupe, D.; Gupta, A.; Hall, P. B.; Hicks, S.; Horenstein, D.; Horne, Keith; Hutchison, T.; Im, M.; Joner, M. D.; Jones, J.; Kaastra, J.; Kaspi, S.; Kelly, B. C.; Kennea, J. A.; Kim, M.; Kim, S. C.; Klimanov, S. A.; Lee, J. C.; Leonard, D. C.; Lira, P.; MacInnis, F.; Mathur, S.; McHardy, I. M.; Montouri, C.; Musso, R.; Nazarov, S. V.; Netzer, H.; Norris, R. P.; Nousek, J. A.; Okhmat, D. N.; Papadakis, I.; Parks, J. R.; Pott, J. U.; Rafter, S. E.; Rix, H. W.; Saylor, D. A.; Schnuelle, K.; Sergeev, S. G.; Siegel, M.; Skielboe, A.; Spencer, M.; Starkey, D.; Sung, H. I.; Teems, K. G.; Turner, C. S.; Uttley, P.; Villforth, C.; Weiss, Y.; Woo, J. H.; Yan, H.; Young, S.; Zu, Y.
    We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The H beta and He II lambda 4686 broad emission-line light curves lag that of the 5100 angstrom optical continuum by 4.17(-0.36)(+0.36) days and 0.79(-0.34)(+0.35) days, respectively. The H beta lag relative to the 1158 angstrom ultraviolet continuum light curve measured by the Hubble Space Telescope is similar to 50% longer than that measured against the optical continuum, and the lag difference is consistent with the observed lag between the optical and ultraviolet continua. This suggests that the characteristic radius of the broad-line region is similar to 50% larger than the value inferred from optical data alone. We also measured velocity-resolved emission-line lags for H beta and found a complex velocity-lag structure with shorter lags in the line wings, indicative of a broadline region dominated by Keplerian motion. The responses of both the H beta and He II emission lines to the driving continuum changed significantly halfway through the campaign, a phenomenon also observed for C IV, Lya, He II (+ O III]), and Si IV(+ O IV]) during the same monitoring period. Finally, given the optical luminosity of NGC 5548 during our campaign, the measured H beta lag is a factor of five shorter than the expected value implied by the R-BLR-L-AGN relation based on the past behavior of NGC 5548.
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    Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy
    (IOP PUBLISHING LTD, 2017) Mathur, S.; Gupta, A.; Page, K.; Pogge, R. W.; Krongold, Y.; Goad, M. R.; Adams, S. M.; Anderson, M. D.; Arevalo, P.; Barth, A. J.; Bazhaw, C.; Beatty, T. G.; Bentz, M. C.; Bigley, A.; Bisogni, S.; Borman, G. A.; Boroson, T. A.; Bottorff, M. C.; Brandt, W. N.; Breeveld, A. A.; Brown, J. E.; Brown, J. S.; Cackett, E. M.; Canalizo, G.; Carini, M. T.; Clubb, K. I.; Comerford, J. M.; Coker, C. T.; Corsini, E. M.; Crenshaw, D. M.; Croft, S.; Croxall, K. V.; Dalla Bonta, E.; Deason, A. J.; Denney, K. D.; De Lorenzo Caceres, A.; De Rosa, G.; Dietrich, M.; Edelson, R.; Ely, J.; Eracleous, M.; Evans, P. A.; Fausnaugh, M. M.; Ferland, G. J.; Filippenko, A. V.; Flatland, K.; Fox, O. D.; Gates, E. L.; Gehrels, N.; Geier, S.; Gelbord, J. M.; Gorjian, V.; Greene, J. E.; Grier, C. J.; Grupe, D.; Hall, P. B.; Henderson, C. B.; Hicks, S.; Holmbeck, E.; Holoien, T. W. S.; Horenstein, D.; Horne, Keith; Hutchison, T.; Im, M.; Jensen, J. J.; Johnson, C. A.; Joner, M. D.; Jones, J.; Kaastra, J.; Kaspi, S.; Kelly, B. C.; Kelly, P. L.; Kennea, J. A.; Kim, M.; Kim, S.; Kim, S. C.; King, A.; Klimanov, S. A.; Kochanek, C. S.; Korista, K. T.; Kriss, G. A.; Lau, M. W.; Lee, J. C.; Leonard, D. C.; Li, M.; Lira, P.; Ma, Z.; MacInnis, F.; Manne Nicholas, E. R.; Malkan, M. A.; Mauerhan, J. C.; McGurk, R.; McHardy, I. M.; Montouri, C.; Morelli, L.; Mosquera, A.; Mudd, D.; Muller Sanchez, F.; Musso, R.; Nazarov, S. V.; Netzer, H.; Nguyen, M. L.; Norris, R. P.; Nousek, J. A.; Ochner, P.; Okhmat, D. N.; Ou Yang, B.; Pancoast, A.; Papadakis, I.; Parks, J. R.; Pei, L.; Peterson, B. M.; Pizzella, A.; Poleski, R.; Pott, J. U.; Rafter, S. E.; Rix, H. W.; Runnoe, J.; Saylor, D. A.; Schimoia, J. S.; Schnuelle, K.; Sergeev, S. G.; Shappee, B. J.; Shivvers, I.; Siegel, M.; Simonian, G. V.; Siviero, A.; Skielboe, A.; Somers, G.; Spencer, M.; Starkey, D.; Stevens, D. J.; Sung, H. I.; Tayar, J.; Tejos, N.; Turner, C. S.; Uttley, P.; Van Saders, J.; Vestergaard, M.; Vican, L.; Villanueva, S., Jr.; Villforth, C.; Weiss, Y.; Woo, J. H.; Yan, H.; Young, S.; Yuk, H.; Zheng, W.; Zhu, W.; Zu, Y.
    During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on-and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly.
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    Supernova 2011D in UGC 2498
    (2011) Narla, A.; Cenko, S. B.; Li, W.; Filippenko, A. V.; Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Marion, G. H.; Challis, P.; Berlind, P.
    Via public images from the Catalina Sky Survey (CSS). 2011 UT R.A. (2000.0) Decl. Mag. Offset Observers Jan. 5.09 3 02 14.58 +17 20 58.9 18.2 33".8 E, 14".7 N CSS Jan. 6.30 3 02 14.53 +17 20 58.3 18.2 34".4 E, 14".8 N KAIT Additional magnitudes for 2011D: 2010 Dec. 8.32 UT, [19.3 (KAIT); 10.19, [19.4 (CSS); 2011 Jan. 7.21, 18.2 (KAIT); 8.13, 17.8 (S. Howerton, remotely with the LB-1 0.6-m telescope near Rodeo, NM, U.S.A.). Drake notes that the presumed host galaxy, UGC 2498, has redshift z = 0.0231. G. H. Marion and P. Challis, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report that a spectrum (range 340-740 nm) was obtained of 2011D on Jan. 8 UT by P. Berlind with the F. L. Whipple Observatory 1.5-m telescope (+ FAST). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011D is a type-IIb supernova a few days before maximum light....
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    Supernova 2011ho in NGC 3847 = Psn J11441295+3330581
    (2011) Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; McNaught, R. H.; Garradd, G.; Beshore, E. C.; Larson, S. M.; Christensen, E.; Foley, R. J.; Kasen, D.; Filippenko, A. V.; Marion, G. H.; Berlind, P.
    Report the discovery of an apparent supernova in public images from the Catalina Sky Survey (CSS). SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011ho Oct. 28.49 11 44 12.95 +33 30 58.1 18.7 12".8 W, 5".8 N This variable was designated PSN J11441295+3330581 when it was posted on the Central Bureau's TOCP webpage and is here designated SN 2011ho based on the spectroscopic confirmation reported below. Further unfiltered CCD magnitudes for 2011ho: June 11.21 UT, [19.0 (CSS); Oct. 30.495, 18.3 (Joseph Brimacombe, Cairns, Australia; position end figures 13s.10, 59".2; image posted at website URL http://www.flickr.com/photos/43846774@N02/6297040020/). R. J. Foley, Harvard-Smithsonian Center for Astrophysics; and D. Kasen and A. V. Filippenko, University of California, Berkeley, report that a CCD spectrum (range 310-1020 nm), obtained on Oct. 31 UT with the Keck I 10-m telescope (+ LRIS), shows that PSN J11441295+3330581 = SN 2011ho is a type-Ia supernova near maximum brightness. The spectrum exhibits a large Si II 597.2-nm/635.5-nm ratio, indicating a cooler photosphere and a lower luminosity. The spectrum is similar to that of SN 1986G at -3 days (Phillips et al. 1987, PASP 99, 592), but it also resembles spectra of the more typical type-Ia supernovae 1992A and 2004eo at a similar epoch. After removing the recession velocity of 9520 km/s (obtained from the Sloan Digital Sky Survey), the minimum of the Si II 635.5-nm feature is blueshifted by 11700 km/s. G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, reports that a spectrum (range 340-740 nm) of PSN J11441295+3330581 = 2011ho was obtained on Nov. 3 UT by P. Berlind with the F. L. Whipple Observatory 1.5-m telescope (+ FAST). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011ho is a 1991bg-like type-Ia supernova near maximum light. Good fits can be found to several templates of normal and 1991bg-like type-Ia supernovae within three days of maximum. The presence of a strong feature from Si II 597.2-nm and the reported brightness of 2011ho are consistent with a subluminous, or 1991bg-like, type-Ia supernova. Using an estimated redshift of z = 0.031829 for NGC 3847 as reported in NED (de Vaucouleurs et al. 1991, RC3.9C), the velocity of the Si II 635.5-nm and 597.2-nm features are estimated to be 10700 km/s and 10500 km/s, respectively....
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    Supernova 2011jt in Pgc 53208 = Psn J14532301+0257431
    (2012) Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Silverman, J. M.; Filippenko, A. V.; Chen, J. -C.; Wang, X. -F.; Zhan, X.; Zhang, T. -M.
    Report the discovery of an apparent supernova in unfiltered Catalina Sky Survey (CSS) images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011jt Dec. 31.54 14 53 23.01 + 2 57 43.1 17.0 5".8 W, 16".4 S The variable was designated PSN J14532301+0257431 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2011jt based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2011jt: 2011 June 23.25 UT, [20.3 (CSS); 2012 Jan. 1.526, 16.5 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + STL11K camera + luminance filter at the New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 23s.02, 42".9; image posted at website URL http://www.flickr.com/photos/43846774@N02/6618245617/). J. M. Silverman and A. V. Filippenko, University of California, Berkeley, report that inspection of a CCD spectrum (range 340-1000 nm), obtained on Jan. 3 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that PSN J14532301+0257431 = SN 2011jt is a type-Ia supernova. After removal of the host-galaxy recession velocity of 8334 km/s (from the Sloan Digital Sky Survey Data Release 1), they find the absorption minimum of the Si II 635.5-nm line to be blueshifted by about 14700 km/s. Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that the object is a normal type-Ia supernova about six days before maximum brightness. J.-C. Chen and X.-F. Wang, Tsinghua Center for Astrophysics, Tsinghua University; X. Zhan, Beijing Planetarium; T.-M. Zhang, National Astronomical Observatory of China (NAOC), report on an optical spectrogram (range 400-8800 nm) of PSN J14532301+0257431 = SN 2011jt that was obtained on 2012 Jan. 3.9 UT with the 2.16-m telescope (+ OMR) at Xinglong Station of NAOC. The spectrum is consistent with a type-Ia supernova at about one week before maximum. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that it matches with SN 2002bo at -9 days. Adopting a recession velocity of 8334 km/s for the host galaxy from the NED, they measure a velocity of the Si II 635.5-nm absorption feature to be about 15000 km/s....