A5056247138- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- SAS software applications and methods
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Nuclear Physics and Applications
- CCD and CMOS Imaging Sensors
- Spectroscopy Techniques in Biomedical and Chemical Research
- Planetary Science and Exploration
- Solar and Space Plasma Dynamics
- Radio Astronomy Observations and Technology
- Advanced Optical Sensing Technologies
- Semiconductor Lasers and Optical Devices
- History and Developments in Astronomy
- Particle accelerators and beam dynamics
- Optical Systems and Laser Technology
Kavli Institute for the Physics and Mathematics of the Universe
2015-2024
The University of Tokyo
2015-2024
San Diego State University
2015-2024
California Institute of Technology
2007-2012
The University of Texas at Austin
2003-2009
Lawrence Berkeley National Laboratory
1999-2007
We report measurements of the mass density, ΩM, and cosmological-constant energy ΩΛ, universe based on analysis 42 type Ia supernovae discovered by Supernova Cosmology Project. The magnitude-redshift data for these supernovae, at redshifts between 0.18 0.83, are fitted jointly with a set from Calán/Tololo Survey, below 0.1, to yield values cosmological parameters. All supernova peak magnitudes standardized using SN light-curve width-luminosity relation. measurement yields joint probability...
The Palomar Transient Factory (PTF) is a fully-automated, wide-field survey aimed at systematic exploration of the optical transient sky. performed using new 8.1 square degree camera installed on 48-inch Samuel Oschin telescope Observatory; colors and light curves for detected transients are obtained with automated 60-inch telescope. PTF uses eighty percent 1.2-m fifty 1.5-m time. With an exposure 60-s reaches depth approximately 21.3 in g' 20.6 R (5 sigma, median seeing). Four major...
The Palomar Transient Factory (PTF) is a wide-field experiment designed to investigate the optical transient and variable sky on time scales from minutes years. PTF uses CFH12k mosaic camera, with field of view 7.9 deg2 plate scale 1'' pixel-1, mounted Observatory 48 inch Samuel Oschin Telescope. operation strategy devised probe existing gaps in phase space search for theoretically predicted, but not yet detected, phenomena, such as fallback supernovae, macronovae,. Ia orphan afterglows...
We report the discovery and early observations of peculiar Type IIn supernova (SN) 2006gy in NGC 1260. With a peak visual magnitude about -22, it is most luminous ever recorded. Its very slow rise to maximum took ~70 days, stayed brighter than -21 mag for 100 days. It not yet clear what powers enormous luminosity total radiated energy ~1051 erg, but we argue that any known mechanism—thermal emission, circumstellar interaction, or 56Ni decay—requires massive progenitor star. The interaction...
Merging neutron stars offer an exquisite laboratory for simultaneously studying strong-field gravity and matter in extreme environments. We establish the physical association of electromagnetic counterpart EM170817 to gravitational waves (GW170817) detected from merging stars. By synthesizing a panchromatic dataset, we demonstrate that are long-sought production site forging heavy elements by r-process nucleosynthesis. The weak gamma-rays seen dissimilar classical short gamma-ray bursts with...
We present the results of a Palomar Transient Factory (PTF) archival search for blue transients which lie in magnitude range between "normal" core-collapse and superluminous supernovae (i.e. with $-21\,{\leq}M_{R\,(peak)}\,{\leq}-19$). Of six events found after excluding all interacting Type~IIn Ia-CSM supernovae, three (PTF09ge, 09axc 09djl) are coincident centers their hosts, one (10iam) is offset from center, two (10nuj 11glr) precise can not be determined. All central have similar rise...
We report the discovery by Swift hard X-ray monitor of transient source J2058.4+0516 (Sw J2058+05). Our multi-wavelength follow-up campaign uncovered a long-lived (duration ≳ months), luminous (LX, iso ≈ 3 × 1047 erg s−1) and radio (νLν, 1042 counterpart. The associated optical emission, however, from which we measure redshift 1.1853, is relatively faint, this not due to large amount dust extinction in host galaxy. Based on numerous similarities with recently discovered GRB 110328A/Swift...
Variable X-ray and gamma-ray emission is characteristic of the most extreme physical processes in Universe, studying sources these energetic photons has been a major driver astronomy for past 50 years. Here we present multiwavelength observations unique selected transient, discovered by Swift, which was accompanied bright across electromagnetic spectrum, whose properties are unlike any previously observed source. We pinpoint event to center small, star-forming galaxy at redshift z=0.3534....
Stellar Explosions Stars that are born with masses greater than eight times of the Sun end their lives in luminous explosions known as supernovae. Over past decade, access to improved sky surveys has revealed rare types supernovae much more any those were before. Gal-Yam (p. 927 ) reviews these superluminous events and groups them into three classes share common observational physical characteristics. Gamma-ray bursts another type extreme explosive related death massive stars, which occur...
We present ultraviolet through near-infrared photometry and spectroscopy of the host galaxies all superluminous supernovae (SLSNe) discovered by Palomar Transient Factory prior to 2013, derive measurements their luminosities, star-formation rates, stellar masses, gas-phase metallicities. find that Type I (hydrogen-poor) SLSNe are found almost exclusively in low-mass (M < 2x10^9 M_sun) metal-poor (12+log[O/H] 8.4) galaxies. compare mass metallicity distributions our sample nearby galaxy...
Wide-field optical surveys have begun to uncover large samples of fast (trise ≲ 5 d), luminous (Mpeak < −18), blue transients. While commonly attributed the breakout a supernova shock into dense wind, great distances transients this class found so far hampered detailed investigation their properties. We present photometry and spectroscopy from comprehensive worldwide campaign observe AT 2018cow (ATLAS 18qqn), first fast-luminous transient be in real time at low redshift. Our spectra (<2 days...
The Nearby Supernova Factory (<i>Snfactory</i>) is an international experiment designed to lay the foundation for next generation of cosmology experiments (such as <i>CFHTLS</i>, <i>w</i>P, <i>SNAP</i> and <i>LSST</i>) which will measure expansion history Universe using Type Ia supernovae. <i>Snfactory</i> discover obtain frequent lightcurve spectrophotometry covering 3200-10000Å roughly 300 supernovae at low-redshift end smooth Hubble flow. quantity, quality, breadth galactic...
We present unfiltered photometric observations with ROTSE-III and optical spectroscopic follow-up the HET Keck of most luminous supernova yet identified, SN 2005ap. The spectra taken about 3 days before 6 after maximum light show narrow emission lines (likely originating in dwarf host) absorption at a redshift z=0.2832, which puts peak magnitude -22.7 +/- 0.1 absolute. Broad P-Cygni features corresponding to H-alpha, CIII, NIII, OIII, are further detected photospheric velocity ~20,000 km/s....
Type Ia supernovae are key tools for measuring distances on a cosmic scale. They generally thought to be the thermonuclear explosion of an accreting white dwarf in close binary system. The nature mass donor is still uncertain. In single-degenerate model it main-sequence star or evolved star, whereas double-degenerate another dwarf. We show that velocity structure absorbing material along line sight 35 type tends blueshifted. These structures likely signatures gas outflows from supernova...
From the first two seasons of Palomar Transient Factory, we identify three peculiar transients (PTF 09dav, PTF 10iuv, and 11bij) with five distinguishing characteristics: peak luminosity in gap between novae supernovae (MR ≈ −15.5 to −16.5 mag), rapid photometric evolution (trise 12–15 days), large photospheric velocities (≈6000–11,000 km s−1), early spectroscopic into nebular phase (≈1–3 months), spectra dominated by calcium. We also culled extensive decade-long Lick Observatory Supernova...
On May 31, 2011 UT a supernova (SN) exploded in the nearby galaxy M51 (the Whirlpool Galaxy). We discovered this event using small telescopes equipped with CCD cameras, as well by Palomar Transient Factory (PTF) survey, and rapidly confirmed it to be Type II supernova. Our early light curve spectroscopy indicates that PTF11eon resulted from explosion of relatively compact progenitor star evidenced rapid shock-breakout cooling seen curve, low temperature early-time spectra prompt appearance...
We use the first compilation of 72 core-collapse supernovae (SNe) from Palomar Transient Factory (PTF) to study their observed subtype distribution in dwarf galaxies compared giant galaxies. Our sample is largest single-survey, untargeted, spectroscopically classified, homogeneous collection events ever assembled, spanning a wide host-galaxy luminosity range (down Mr ≈ −14 mag) and including substantial fraction (>20%) (Mr ⩾ −18 hosts. find more SNe than expected several interesting trends...
Type-IIn supernovae (SNe), which are characterized by strong interaction of their ejecta with the surrounding circumstellar matter (CSM), provide a unique opportunity to study mass-loss history massive stars shortly before explosive death. We present discovery and follow-up observations Type IIn SN, PTF 09uj, detected Palomar Transient Factory (PTF). Serendipitous GALEX at ultraviolet (UV) wavelengths rise SN light curve prior discovery. The UV rose fast, time scale few days, absolute AB...
The rate of image acquisition in modern synoptic imaging surveys has already begun to outpace the feasibility keeping astronomers real-time discovery and classification loop. Here we present inner workings a framework, based on machine-learning algorithms, that captures expert training ground-truth knowledge about variable transient sky automate 1) process differences and, 2) generation preliminary science-type classifications discovered sources. Since follow-up resources for extracting...
We calculate the volumetric rate of superluminous supernovae (SLSNe) based on 5 events discovered with ROTSE-IIIb telescope. gather light curves 19 from literature and our own unpublished data employ crude k-corrections to constrain pseudo-absolute magnitude distributions in rest frame (unfiltered) band pass for both hydrogen poor (SLSN-I) rich (SLSN-II) populations. find that peak magnitudes available SLSN-I are narrowly distributed ($M = -21.7 \pm 0.4$) unfiltered may suggest an even...
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....