A5027876991- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Non-Destructive Testing Techniques
- Superconducting Materials and Applications
- Calibration and Measurement Techniques
- Neutrino Physics Research
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Astrophysics and Star Formation Studies
- Atmospheric Ozone and Climate
- Electrical Fault Detection and Protection
- Cosmology and Gravitation Theories
- Cardiac, Anesthesia and Surgical Outcomes
- Thyroid Cancer Diagnosis and Treatment
- Helicobacter pylori-related gastroenterology studies
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- Engineering Applied Research
Groupe Hospitalier Diaconesses Croix Saint-Simon
2025
Château Gombert
2017-2024
Laboratoire d’Astrophysique de Marseille
2012-2024
Aix-Marseille Université
2012-2024
Centre National de la Recherche Scientifique
2012-2024
European Southern Observatory
2004-2024
Centre National d'Études Spatiales
2024
Pontificia Universidad Católica de Chile
2019-2023
Telescopio Nazionale Galileo
2023
University of Cambridge
2022
We present constraints on the dark energy equation-of-state parameter, w=P/(rho c^2), using 60 Type Ia supernovae (SNe Ia) from ESSENCE supernova survey. derive a set of nature assuming flat Universe. By including (Omega_M, w) baryon acoustic oscillations, we obtain value for static parameter w=-1.05^{+0.13}_{-0.12} (stat; 1 sigma) +- 0.11 (sys) and Omega_M=0.274^{+0.033}_{-0.020} with best-fit chi^2/DoF 0.96. These results are consistent those reported by SuperNova Legacy Survey in similar...
We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from literature to calculate improved constraints on dark energy equation of state parameter, w. The is added Union set Kowalski et al. form Constitution and, combined a BAO prior, produces 1 + w = 0.013+0.066−0.068 (0.11 syst), consistent cosmological constant. addition makes cosmologically useful nearby SN between 2.6 and 2.9 times larger than before, reducing statistical uncertainty point where systematics play largest...
The first cosmological results from the ESSENCE supernova survey (Wood-Vasey and coworkers) are extended to a wider range of models including dynamical dark energy nonstandard models. We fold in greater number external data sets such as recent Higher-z release high-redshift supernovae (Riess coworkers), well several complementary probes. Model comparison statistics Bayesian Akaike information criteria applied gauge worth These favor that give good fit with fewer parameters. Based on this...
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
We present an algorithm to identify the type of SN spectrum and determine its redshift age. This algorithm, based on correlation techniques Tonry & Davis, is implemented in Supernova Identification (SNID) code. It used by members ongoing high-redshift searches distinguish between Ia Ib/c SNe, "peculiar" SNe Ia. develop a diagnostic quantify quality input template spectra, which enables formal evaluation associated error. Furthermore, comparing redshifts obtained using SNID with those...
We present photometric and spectroscopic observations of 23 high-redshift supernovae (SNe) spanning a range z = 0.34-1.03, nine which are unambiguously classified as Type Ia. These SNe were discovered during the IfA Deep Survey, began in 2001 September observed total 2.5 deg2 to depth approximately m ≈ 25-26 RIZ over 9-17 visits, typically every 1-3 weeks for nearly 5 months, with additional continuing until 2002 April. give brief description survey motivations, observational strategy,...
Abstract The Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy, and, as such, it offer unique opportunities to address many key astrophysical questions in completely novel way. synergy with ground-based and space-born instruments the electromagnetic domain, by enabling multi-messenger observations, add further discovery potential of LISA. next decade is crucial prepare community LISA’s first observations. This review outlines...
We present 2603 spectra of 462 nearby Type Ia supernovae (SNe Ia), including 2065 previously unpublished spectra, obtained during 1993–2008 through the Center for Astrophysics Supernova Program. There are on average eight each 313 SNe with at least two spectra. Most were FAST spectrograph Fred Lawrence Whipple Observatory 1.5 m telescope and reduced in a consistent manner, making this data set well suited studies SN spectroscopic diversity. Using additional from literature, we study...
Spectra and light curves of SN 2006gz show the strongest signature unburned carbon one slowest fading ever seen in a Type Ia event [Δm15(B) = 0.69 ± 0.04]. The early-time Si II velocity is low, implying it was slowed by an envelope material. Our best estimate luminosity implies MV -19.74 production ~1.2 M☉ 56Ni. This suggests super-Chandrasekhar mass progenitor. A double degenerate merger consistent with these observations.
We describe the implementation and optimization of ESSENCE supernova survey, which we have undertaken to measure equation state parameter dark energy. present a method for optimizing survey exposure times cadence maximize our sensitivity energy w=P/rho c^2 given fixed amount telescope time. For on CTIO 4m telescope, measuring luminosity distances redshifts supernovae at modest (z~0.5 +- 0.2) is optimal determining w. data analysis pipeline based using reliable robust image subtraction find...
We present extensive early photometric (ultraviolet through near-infrared) and spectroscopic (optical data on supernova (SN) 2008D as well X-ray analysis the associated Swift transient (XRT) 080109. Our span a time range of 5 hr before detection to 150 days after its detection, detailed allowed us derive constraints nature SN progenitor; throughout we draw comparisons with results presented in literature find several key aspects that differ. show spectrum XRT 080109 can be fit equally by an...
Much uncertainty surrounds the origin of super-luminous supernovae (SNe). Motivated by discovery Type Ic SN2007bi, we study its proposed association with a pair-instability SN (PISN). We compute stellar-evolution models for primordial ~200Msun stars, simulating implosion/explosion due to pair-production instability, and use them as inputs detailed non-LTE time-dependent radiative-transfer simulations that include non-local energy deposition non-thermal processes. retrieve basic morphology...
We present 645 optical spectra of 73 supernovae (SNe) Types IIb, Ib, Ic, and broad-lined Ic. All these types are attributed to the core collapse massive stars, with varying degrees intact H He envelopes before explosion. The SNe in our sample have a mean redshift 〈cz〉 = 4200 km s−1. Most were gathered at Harvard-Smithsonian Center for Astrophysics (CfA) between 2004 2009. For 53 SNe, first published spectra. data coverage ranges from mere identification (1–3 spectra) few extensive series...
We have obtained 1087 NIR (JHKs) measurements of 21 SNe Ia using PAIRITEL, nearly doubling the number well-sampled SN light curves. These data strengthen evidence that are excellent standard candles in NIR, even without correction for optical light-curve shape. construct fiducial templates normal from our sample, excluding only three known peculiar Ia: 2005bl, 2005hk, and 2005ke. The H-band absolute magnitudes this sample 18 an intrinsic rms 0.15 mag with no found a relationship between...
Recent observations have revealed that some Type Ia supernovae exhibit narrow, time-variable Na i D absorption features. The origin of the absorbing material is controversial, but it may suggest presence circumstellar gas in progenitor system prior to explosion, with significant implications for nature supernova (SN) progenitors. We present third detection such variable absorption, based on six epochs high-resolution spectroscopy SN 2007le from Keck I Telescope and Hobby–Eberly Telescope....
Recent high-resolution spectra of the Type Ia supernova SN 2006X have revealed presence time-variable and blueshifted Na i D features, interpreted by Patat et al. as originating in circumstellar material within progenitor system. The variation seen induces relatively large changes total equivalent width (ΔEW ∼ 0.5 Å just over two weeks) that would be detectable at lower resolutions. We used a data set comprising 2400 low-resolution 450 supernovae (SNe Ia) obtained CfA Supernova Program to...
We present non-LTE time-dependent radiative-transfer simulations of pair-instability supernovae (PISNe) stemming from red-supergiant (RSG), blue-supergiant (BSG) and Wolf-Rayet (WR) star rotation-free progenitors born in the mass range 160-230Msun, at 10^-4 Zsun. Although subject to uncertainties convection stellar mass-loss rates, our initial conditions come physically-consistent models that treat evolution main-sequence, onset pair-production instability, explosion phase. With set input...
The delayed-detonation explosion mechanism applied to a Chandrasekhar-mass white dwarf offers very attractive model explain the inferred characteristics of Type Ia supernovae (SNe Ia). resulting ejecta are chemically stratified, have same mass and roughly asymptotic kinetic energy, but exhibit range in 56Ni mass. We investigate contemporaneous photometric spectroscopic properties sequence models, characterized by masses between 0.18 0.81 Msun. Starting at 1d after explosion, we perform full...
Abstract Type Ia supernovae (SNe Ia) span a range of luminosities and timescales, from rapidly evolving subluminous to slowly overluminous subtypes. Previous theoretical work has, for the most part, been unable match entire breadth observed SNe with one progenitor scenario. Here, first time, we apply non-local thermodynamic equilibrium radiative transfer calculations accurate explosion models sub-Chandrasekhar-mass white dwarf detonations. The resulting photometry spectra are in excellent...
We present early photometric and spectroscopic data on the afterglow of GRB 060218 report evolution underlying supernova SN 2006aj. Our span a time range 4-23 days after clearly establish that 2006aj is fast-evolving broad-lined Type Ic with an extremely short rise (~10 days) large optical peak luminosity (MV = -18.7 mag). The properties are deduced well since gamma-ray burst (GRB) does not contribute significant amount to total light output. spectra show broad lines indicative expansion...
We analyze the Type II plateau supernovae (SNe IIP) SN 2005cs and 2006bp with non-LTE model atmosphere code CMFGEN. fit 13 spectra in first month for 18 2006bp. Swift ultraviolet photometry ground-based optical calibrate each spectrum. Our analysis shows that both objects were discovered less than 3 days after they exploded, making these earliest IIP ever studied. They reveal broad very weak lines from highly ionized fast ejecta an extremely steep density profile. identify He λ4686 emission...
Double-peaked oxygen lines in the nebular spectra of two peculiar Type Ib/c supernovae (SNe Ib/c) have been interpreted as off-axis views a GRB jet or unipolar blob ejections. Here we present late-time eight SNe IIb, Ib, and Ic show that this phenomenon is common should not be so firmly linked to extraordinary explosion physics. The line profiles are most likely caused by ejecta expanding with torus- disk-like geometry. necessarily indicator misdirected jet.
We present 432 low-dispersion optical spectra of 32 Type Ia supernovae (SNe Ia) that also have well-calibrated light curves. The coverage ranges from 6 epochs to 36 spectroscopy. Most the data were obtained with 1.5 m Tillinghast telescope at F. L. Whipple Observatory typical wavelength 3700–7400 Å and a resolution ∼7 Å. earliest are 13 days before B-band maximum; two-thirds SNe observed maximum brightness. Coverage for some continues almost nebular phase. consistency method observation...
We report the successful identification of type supernova responsible for remnant SNR 0509-675 in Large Magellanic Cloud (LMC) using Gemini spectra surrounding light echoes. The ability to classify outbursts associated with centuries-old remnants provides a new window into several aspects research and is likely be providing constraints on additional LMC supernovae as well their historical counterparts Milky Way Galaxy (MWG). combined spectrum echo from shows broad emission absorption lines...
Observations of SN 2011fe at early times reveal an evolution analogous to a fireball model constant color. In contrast, our unmixed delayed detonations Chandrasekhar-mass white dwarfs (DDC series) exhibit faster brightening concomitant with shift in color the blue. this paper, we study origin these discrepancies. We find that strong chemical mixing largely resolves photometric mismatch times, but it leads enhanced line broadening contrasts, for example, markedly narrow SiII6355A 2011fe. also...