A. Gal‐Yam
A5053406766- Gamma-ray bursts and supernovae
- Optical Systems and Laser Technology
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Integrated Circuits and Semiconductor Failure Analysis
- Advancements in Semiconductor Devices and Circuit Design
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Semiconductor materials and devices
- Neutrino Physics Research
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- SAS software applications and methods
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Non-Destructive Testing Techniques
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Spacecraft and Cryogenic Technologies
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- CCD and CMOS Imaging Sensors
Weizmann Institute of Science
2016-2025
South African Radio Astronomy Observatory
2024
Astronomical Observatory
2024
Cerro Tololo Inter-American Observatory
2024
Queen Mary University of London
2010
California Institute of Technology
2004-2009
Tel Aviv University
1997-2007
Collurania Teramo Observatory
2007
Osservatorio Astronomico di Padova
2007
University of Padua
2007
The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides 47 deg2 field of view and 8 s readout time, yielding more than an order magnitude improvement in speed relative to its predecessor survey, Factory. We describe design implementation observing system. ZTF data system at Infrared Processing Analysis Center near-real-time reduction identify moving varying objects. outline analysis...
A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of exciting science opportunities next decade. The Large Synoptic Survey Telescope (LSST) have an effective aperture 6.7 meters and imaging camera field view 9.6 deg^2, be devoted ten-year 20,000 deg^2 south +15 deg. Each pointing imaged 2000 times fifteen second exposures six broad from 0.35 1.1 microns, total point-source depth r~27.5. LSST Science Book describes basic...
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...
We have entered an era of massive data sets in astronomy. In particular, the number supernova (SN) discoveries and classifications has substantially increased over years from few tens to thousands per year. It is no longer case that observations a prototypical events encapsulate most spectroscopic information about SNe, motivating development modern tools collect, archive, organize, distribute spectra general SN particular. For this reason, we developed Weizmann Interactive Supernova Data...
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...
The Zwicky Transient Facility (ZTF), a public-private enterprise, is new time domain survey employing dedicated camera on the Palomar 48-inch Schmidt telescope with 47 deg$^2$ field of view and 8 second readout time. It well positioned in development astronomy, offering operations at 10% scale style Large Synoptic Survey Telescope (LSST) single 1-m class telescope. public surveys will cover observable northern sky every three nights g r filters visible Galactic plane night r. Alerts...
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...
Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. [ABRIDGED], now have 58 microlensed bulge dwarfs subgiants that been homogeneously analysed. The main characteristics sample findings can be drawn are: (i) metallicity distribution (MDF) is wide spans all metallicities between [Fe/H]=-1.9 to +0.6; (ii) dip MDF around solar was apparent our previous smaller...
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...
Type Ia supernovae are important cosmological distance indicators. Each of these bright supposedly results from the thermonuclear explosion a white dwarf star that, after accreting material companion star, exceeds some mass limit, but true nature progenitor system remains controversial. Here we report spectroscopic detection circumstellar in normal type supernova explosion. The expansion velocities, densities, and dimensions envelope indicate that this was ejected system. In particular,...
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...
We present photometric and spectroscopic observations of SN 2007if, an overluminous (MV = −20.4), red (B − V 0.16 at B-band maximum), slow-rising (trise 24 days) type Ia supernova (SN Ia) in a very faint (Mg −14.10) host galaxy. A spectrum 5 days past maximum light is direct match to the super-Chandrasekhar-mass candidate 2003fg, showing Si ii C ∼9000 km s−1. high signal-to-noise co-addition spectral time series reveals no Na i D absorption, suggesting negligible reddening galaxy, late-time...
We present the first measurement of planet frequency beyond "snow line," for planet-to-star mass-ratio interval −4.5 < log q −2, corresponding to range ice giants gas giants. find at mean mass ratio = 5 × 10−4 with no discernible deviation from a flat (Öpik's law) distribution in log-projected separation s. The determination is based on sample six planets detected intensive follow-up observations high-magnification (A>200) microlensing events during 2005–2008. sampled host stars have typical...
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...