Naohiro Takanashi
University of Tokyo
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The Astrophysical Journal | 2012
Nao Suzuki; D. Rubin; C. Lidman; Gregory Scott Aldering; R. Amanullah; K. Barbary; L. F. Barrientos; J. Botyánszki; Mark Brodwin; Natalia Connolly; Kyle S. Dawson; Arjun Dey; Mamoru Doi; Megan Donahue; Susana Elizabeth Deustua; Peter R. M. Eisenhardt; Erica Ellingson; L. Faccioli; V. Fadeyev; H. K. Fakhouri; Andrew S. Fruchter; David G. Gilbank; Michael D. Gladders; G. Goldhaber; Anthony H. Gonzalez; Ariel Goobar; A. Gude; T. Hattori; Henk Hoekstra; E. Y. Hsiao
We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe Ia were discovered over the redshift interval 0.623 1 SNe Ia. We describe how such a sample could be efficiently obtained by targeting cluster fields with WFC3 on board HST. The updated supernova Union2.1 compilation of 580 SNe is available at http://supernova.lbl.gov/Union.
The Astronomical Journal | 2008
Joshua A. Frieman; Bruce A. Bassett; Andrew Cameron Becker; Changsu Choi; D. Cinabro; F. DeJongh; D. L. DePoy; Ben Dilday; Mamoru Doi; Peter Marcus Garnavich; Craig J. Hogan; Jon A. Holtzman; Myungshin Im; Saurabh W. Jha; Richard Kessler; Kohki Konishi; Hubert Lampeitl; John P. Marriner; J. L. Marshall; David P. McGinnis; Gajus A. Miknaitis; Robert C. Nichol; Jose Luis Palacio Prieto; Adam G. Riess; Michael W. Richmond; Roger W. Romani; Masao Sako; Donald P. Schneider; Mathew Smith; Naohiro Takanashi
The Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type Ia supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5° wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for the discovery of new objects. Supernova imaging observations are being acquired between September 1 and November 30 of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe II, plus a large number of photometrically identified SNe Ia, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.
The Astronomical Journal | 2008
M. Sako; Bruce A. Bassett; Andrew Cameron Becker; D. Cinabro; F. DeJongh; D. L. DePoy; Ben Dilday; Mamoru Doi; Joshua A. Frieman; Peter Marcus Garnavich; Craig J. Hogan; Jon A. Holtzman; Saurabh W. Jha; Richard Kessler; Kohki Konishi; Hubert Lampeitl; John P. Marriner; Gajus A. Miknaitis; Robert C. Nichol; Jose Luis Palacio Prieto; Adam G. Riess; Michael W. Richmond; Roger W. Romani; Donald P. Schneider; Mathew Smith; Mark SubbaRao; Naohiro Takanashi; Kouichi Tokita; Kurt van der Heyden; Naoki Yasuda
The Sloan Digital Sky Survey-II Supernova Survey has identified a large number of new transient sources in a 300 deg2 region along the celestial equator during its first two seasons of a three-season campaign. Multi-band (ugriz) light curves were measured for most of the sources, which include solar system objects, galactic variable stars, active galactic nuclei, supernovae (SNe), and other astronomical transients. The imaging survey is augmented by an extensive spectroscopic follow-up program to identify SNe, measure their redshifts, and study the physical conditions of the explosions and their environment through spectroscopic diagnostics. During the survey, light curves are rapidly evaluated to provide an initial photometric type of the SNe, and a selected sample of sources are targeted for spectroscopic observations. In the first two seasons, 476 sources were selected for spectroscopic observations, of which 403 were identified as SNe. For the type Ia SNe, the main driver for the survey, our photometric typing and targeting efficiency is 90%. Only 6% of the photometric SN Ia candidates were spectroscopically classified as non-SN Ia instead, and the remaining 4% resulted in low signal-to-noise, unclassified spectra. This paper describes the search algorithm and the software, and the real-time processing of the SDSS imaging data. We also present the details of the supernova candidate selection procedures and strategies for follow-up spectroscopic and imaging observations of the discovered sources.
The Astronomical Journal | 2008
Jon A. Holtzman; John P. Marriner; Richard Kessler; M. Sako; Ben Dilday; Joshua A. Frieman; Donald P. Schneider; Bruce A. Bassett; Andrew Cameron Becker; D. Cinabro; F. DeJongh; D. L. DePoy; Mamoru Doi; Peter Marcus Garnavich; Craig J. Hogan; Saurabh W. Jha; Kohki Konishi; Hubert Lampeitl; J. L. Marshall; David P. McGinnis; Gajus A. Miknaitis; Robert C. Nichol; Jose Luis Palacio Prieto; Adam G. Riess; Michael W. Richmond; Roger W. Romani; Mathew Smith; Naohiro Takanashi; Kouichi Tokita; Kurt van der Heyden
We present ugriz light curves for 146 spectroscopically-confirmed or spectroscopically-probable Type Ia supernovae (SNe) from the 2005 season of the Sloan Digital Sky Survey-II Supernova (SN) survey. The light curves have been constructed using a photometric technique that we call scene modeling, which is described in detail here; the major feature is that SN brightnesses are extracted from a stack of images without spatial resampling or convolution of the image data. This procedure produces accurate photometry along with accurate estimates of the statistical uncertainty, and can be used to derive photometry taken with multiple telescopes. We discuss various tests of this technique that demonstrate its capabilities. We also describe the methodology used for the calibration of the photometry, and present calibrated magnitudes and fluxes for all of the spectroscopic SNe Ia from the 2005 season.
The Astrophysical Journal | 2009
K. Barbary; Kyle S. Dawson; Kouichi Tokita; Gregory Scott Aldering; Rahman Amanullah; Natalia Connolly; Mamoru Doi; L. Faccioli; V. Fadeyev; Andrew S. Fruchter; Gerson Goldhaber; Ariel Goobar; A. Gude; X. Huang; Yutaka Ihara; Kohki Konishi; M. Kowalski; C. Lidman; Joshua Meyers; P. Nugent; S. Perlmutter; D. Rubin; David J. Schlegel; A. L. Spadafora; Nao Suzuki; H. Swift; Naohiro Takanashi; R. C. Thomas; Norihito Yasuda
We present observations of SCP 06F6, an unusual optical transient discovered during the Hubble Space Telescope Cluster Supernova Survey. The transient brightened over a period of ~;;100 days, reached a peak magnitude of ~;;21.0 in both i_775 and z_850, and then declined over a similar timescale. There is no host galaxy or progenitor star detected at the location of the transient to a 3 sigma upper limit of i_775 = 26.4 and z_850 = 26.1, giving a corresponding lower limit on the flux increase of a factor of ~;;120. Multiple spectra show five broad absorption bands between 4100 AA and 6500 AA and a mostly featureless continuum longward of 6500 AA. The shape of the lightcurve is inconsistent with microlensing. The transients spectrum, in addition to being inconsistent with all known supernova types, is not matched to any spectrum in the Sloan Digital Sky Survey (SDSS) database. We suggest that the transient may be one of a new class.
The Astrophysical Journal | 2008
Benjamin E. P. Dilday; Richard Kessler; Joshua A. Frieman; Jon A. Holtzman; John P. Marriner; Gajus A. Miknaitis; Robert C. Nichol; Roger W. Romani; M. Sako; Bruce A. Bassett; Andrew Cameron Becker; D. Cinabro; F. DeJongh; D. L. DePoy; Mamoru Doi; Peter Marcus Garnavich; Craig J. Hogan; Saurabh W. Jha; Kohki Konishi; Hubert Lampeitl; J. L. Marshall; David P. McGinnis; Jose Luis Palacio Prieto; Adam G. Riess; Michael W. Richmond; Donald P. Schneider; Mathew Smith; Naohiro Takanashi; Kouichi Tokita; Kurt van der Heyden
We present a measurement of the rate of Type Ia supernovae (SNe Ia) from the first of three seasons of data from the SDSS-II Supernova Survey. For this measurement, we include 17 SNe Ia at redshift z ≤ 0.12. Assuming a flat cosmology with Ωm = 0.3 = 1 − ΩΛ, we find a volumetric SN Ia rate of [ 2.93+ 0.17−0.04(systematic)+ 0.90−0.71(statistical) ] × 10−5 SNe Mpc −3 h370 yr −1, at a volume-weighted mean redshift of 0.09. This result is consistent with previous measurements of the SN Ia rate in a similar redshift range. The systematic errors are well controlled, resulting in the most precise measurement of the SN Ia rate in this redshift range. We use a maximum likelihood method to fit SN rate models to the SDSS-II Supernova Survey data in combination with other rate measurements, thereby constraining models for the redshift evolution of the SN Ia rate. Fitting the combined data to a simple power-law evolution of the volumetric SN Ia rate, rV ∝ (1 + z)β, we obtain a value of β = 1.5 ± 0.6, i.e., the SN Ia rate is determined to be an increasing function of redshift at the ~2.5 σ level. Fitting the results to a model in which the volumetric SN rate is rV = Aρ(t) + B(t), where ρ (t) is the stellar mass density and (t) is the star formation rate, we find A = (2.8 ± 1.2) × 10−14 SNe M−1☉ yr −1, B = (9.3+ 3.4−3.1) × 10−4 SNe M−1☉.
The Astronomical Journal | 2009
Kyle S. Dawson; G. Aldering; R. Amanullah; K. Barbary; L. F. Barrientos; Mark Brodwin; Natalia Connolly; Arjun Dey; Mamoru Doi; Megan Donahue; Peter R. M. Eisenhardt; Erica Ellingson; L. Faccioli; V. Fadeyev; H. K. Fakhouri; Andrew S. Fruchter; David G. Gilbank; Michael D. Gladders; G. Goldhaber; Anthony H. Gonzalez; Ariel Goobar; A. Gude; T. Hattori; Henk Hoekstra; X. Huang; Yutaka Ihara; Buell T. Jannuzi; David E. Johnston; K. Kashikawa; Benjamin P. Koester
We present a new survey strategy to discover and study high-redshift Type Ia supernovae (SNe Ia) using the Hubble Space Telescope (HST). By targeting massive galaxy clusters at 0.9 0.95, nine of which were in galaxy clusters. This strategy provides an SN sample that can be used to decouple the effects of host-galaxy extinction and intrinsic color in high-redshift SNe, thereby reducing one of the largest systematic uncertainties in SN cosmology.
The Astronomical Journal | 2008
C. Zheng; Roger W. Romani; Masao Sako; John P. Marriner; Bruce A. Bassett; Andrew Cameron Becker; Changsu Choi; D. Cinabro; F. DeJongh; D. L. DePoy; Benjamin E. P. Dilday; Mamoru Doi; Joshua A. Frieman; Peter Marcus Garnavich; Craig J. Hogan; Jon A. Holtzman; Myungshin Im; Saurabh W. Jha; Richard Kessler; Kohki Konishi; Hubert Lampeitl; J. L. Marshall; David P. McGinnis; Gajus A. Miknaitis; Robert C. Nichol; Jose Luis Palacio Prieto; Adam G. Riess; Michael W. Richmond; Donald P. Schneider; Mathew Smith
This paper presents spectroscopy of supernovae (SNe) discovered in the first season of the Sloan Digital Sky Survey-II SN Survey. This program searches for and measures multi-band light curves of SNe in the redshift range z = 0.05-0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the SN population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our SN spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the SN and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host-galaxy contamination existing in the majority of our SN spectra.
The Astrophysical Journal | 2012
K. Barbary; Gregory Scott Aldering; Rahman Amanullah; Mark Brodwin; Natalia Connolly; Kyle S. Dawson; Mamoru Doi; Peter R. M. Eisenhardt; L. Faccioli; V. Fadeyev; Hannah Fakhouri; Andrew S. Fruchter; David G. Gilbank; Michael D. Gladders; Gerson Goldhaber; Ariel Goobar; T. Hattori; E. Y. Hsiao; X. Huang; Yutaka Ihara; Nobunari Kashikawa; Benjamin P. Koester; Kohki Konishi; M. Kowalski; C. Lidman; Lori M. Lubin; Joshua Meyers; Takeshi Oda; Nino Panagia; S. Perlmutter
We report a measurement of the Type Ia supernova (SN Ia) rate in galaxy clusters at 0.9 0.9 SNe. Finding 8 +/- 1 cluster SNe Ia, we determine an SN Ia rate of 0.50(-0.19)(+0.23) (stat) (+0.10)(-0.09) (sys) h(70)(2) SNuB (SNuB equivalent to 10(-12) SNe (L-1)circle dot(,B) yr(-1)). In units of stellar mass, this translates to 0.36(-0.13)(+0.16) (stat) (+0.07)(-0.06) (sys) h(70)(2) SNuM (SNuM = 10(-12) SNe M-1 circle dot yr(-1)). This represents a factor of approximate to 5 +/- 2 increase over measurements of the cluster rate at z < 0.2. We parameterize the late-time SN Ia delay time distribution (DTD) with a power law: Psi(t) t(s). Under the approximation of a single-burst cluster formation redshift of z(f) = 3, our rate measurement in combination with lower-redshift cluster SN Ia rates constrains s = -1.41(-0.40)(+0.47), consistent with measurements of the DTD in the field. This measurement is generally consistent with expectations for the double degenerate scenario and inconsistent with some models for the single degenerate scenario predicting a steeper DTD at large delay times. We check for environmental dependence and the influence of younger stellar populations by calculating the rate specifically in cluster red-sequence galaxies and in morphologically early-type galaxies, finding results similar to the full cluster rate. Finally, the upper limit of one hostless cluster SN Ia detected in the survey implies that the fraction of stars in the intra-cluster medium is less than 0.47 (95% confidence), consistent with measurements at lower redshifts.
The Astrophysical Journal | 2012
K. Barbary; Gregory Scott Aldering; R. Amanullah; Mark Brodwin; Natalia Connolly; Kyle S. Dawson; Mamoru Doi; Peter R. M. Eisenhardt; L. Faccioli; V. Fadeyev; H. K. Fakhouri; Andrew S. Fruchter; David G. Gilbank; Michael D. Gladders; G. Goldhaber; Ariel Goobar; T. Hattori; E. Y. Hsiao; X. Huang; Yutaka Ihara; Nobunari Kashikawa; Benjamin P. Koester; Kohki Konishi; M. Kowalski; C. Lidman; Lori M. Lubin; Joshua Meyers; Takeshi Oda; Nino Panagia; S. Perlmutter
We present a measurement of the volumetric Type Ia supernova (SN Ia) rate out to z similar or equal to 1.6 from the Hubble Space Telescope Cluster Supernova Survey. In observations spanning 189 orbits with the Advanced Camera for Surveys we discovered 29 SNe, of which approximately 20 are SNe Ia. Twelve of these SNe Ia are located in the foregrounds and backgrounds of the clusters targeted in the survey. Using these new data, we derive the volumetric SN Ia rate in four broad redshift bins, finding results consistent with previous measurements at z greater than or similar to 1 and strengthening the case for an SN Ia rate that is greater than or similar to 0.6 x 10(-4) h(70)(3) yr(-1) Mpc(-3) at z similar to 1 and flattening out at higher redshift. We provide SN candidates and efficiency calculations in a form that makes it easy to rebin and combine these results with other measurements for increased statistics. Finally, we compare the assumptions about host-galaxy dust extinction used in different high-redshift rate measurements, finding that different assumptions may induce significant systematic differences between measurements.