Suvi Gezari
A5085143798- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- SAS software applications and methods
- Astrophysics and Star Formation Studies
- Optical Systems and Laser Technology
- Radio Astronomy Observations and Technology
- Photocathodes and Microchannel Plates
- Neutrino Physics Research
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Integrated Circuits and Semiconductor Failure Analysis
- Methane Hydrates and Related Phenomena
- Relativity and Gravitational Theory
- History and Developments in Astronomy
- Reservoir Engineering and Simulation Methods
- Mechanics and Biomechanics Studies
Johns Hopkins University
2008-2024
Space Telescope Science Institute
2021-2024
University of Maryland, College Park
2014-2024
Bloomberg (United States)
2011-2024
Goddard Space Flight Center
2019-2024
JSS Science and Technology University
2022
Joint Space Science Institute
2017-2021
Deleted Institution
2019
University of California, Santa Cruz
2018
California Institute of Technology
2006-2011
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...
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...
In the past decade, several rapidly evolving transients have been discovered whose timescales and luminosities are not easily explained by traditional supernovae (SNe) models. The sample size of these objects has remained small due, at least in part, to challenges detecting short timescale with survey cadences. Here we present results from a search within Pan-STARRS1 Medium Deep Survey (PS1-MDS) for luminous transients. We identify 10 new time above half-maximum (t1/2) less than 12 days...
The concept of stars being tidally ripped apart and consumed by a massive black hole (MBH) lurking in the center galaxy first captivated theorists late 1970's. observational evidence for these rare but illuminating phenomena probing otherwise dormant MBHs, emerged archival searches soft X-ray ROSAT All-Sky Survey 1990's; has recently accelerated with increasing survey power optical time domain, tidal disruption events (TDEs) now regarded as class nuclear transients distinct spectroscopic...
Using archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data (Stripe 82), we have searched for the tidal disruption of stars by supermassive black holes in non-active galaxies. Two candidate events (TDEs) are identified. The TDE flares optical blackbody temperatures 2 × 104 K and observed peak luminosities Mg = −18.3 −20.4 (νLν 5 1042, 4 1043 erg s−1, rest frame); their cooling rates very low, qualitatively consistent with expectations flares. properties candidates examined using...
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...
Tidal disruption events (TDEs) offer a unique way to study dormant black holes. While the number of observed TDEs has grown thanks emergence wide-field surveys in past few decades, questions regarding nature optical, UV, and X-ray emission remain. We present uniformly selected sample 30 spectroscopically classified from Zwicky Transient Facility Phase I survey operations with follow-up \textit{Swift} UV observations. Through our investigation into correlations between light curve properties,...
The origins of the high-energy cosmic neutrino flux remain largely unknown. Recently, one was associated with a tidal disruption event (TDE). Here we present AT2019fdr, an exceptionally luminous TDE candidate, coincident another neutrino. Our observations, including bright dust echo and soft late-time x-ray emission, further support origin this flare. probability finding two such events by chance is just 0.034%. We evaluate several models for production show that AT2019fdr capable producing...
Abstract We conduct a systematic tidal disruption event (TDE) demographics analysis using the largest sample of optically selected TDEs. A flux-limited, spectroscopically complete 33 TDEs is constructed Zwicky Transient Facility over 3 yr (from 2018 October to 2021 September). infer black hole (BH) mass ( M BH ) with host galaxy scaling relations, showing that ranges from 10 5.1 ⊙ 8.2 . developed survey efficiency corrected maximum volume method rates. The rest-frame g -band luminosity...
Abstract We present a systematic analysis of the X-ray emission sample 17 optically selected, X-ray-detected tidal disruption events (TDEs) discovered between 2014 and 2021. The light curves show diverse range temporal behaviors, with most sources not following expected power-law decline. spectra are mostly extremely soft consistent thermal from innermost region an accretion disk, which cools as rate decreases. Three formation hard corona at late times. spectral energy distribution shape,...
ABSTRACT The origin of cosmic high-energy neutrinos remains largely unexplained. For neutrino alerts from IceCube, a coincidence with time-variable emission has been seen for three different types accreting black holes: (1) gamma-ray flare blazar (TXS 0506+056), (2) an optical transient following stellar tidal disruption event (TDE; AT2019dsg), and (3) outburst active galactic nucleus (AGN; AT2019fdr). the latter two sources, infrared follow-up observations revealed powerful reverberation...
Abstract The JWST Advanced Deep Extragalactic Survey (JADES) is a multicycle program that has taken among the deepest near- and mid-infrared images to date (down ∼30 AB mag) over ∼25 arcmin 2 in GOODS-S field two sets of observations with 1 yr separation. This presented first opportunity systematically search for transients, mostly supernovae (SNe), out z > 2. We found 79 SNe: 38 at < 2, 23 3, 8 3 4, 7 4 5, undetermined redshifts, where redshifts are predominantly based on...
Recent searches by unbiased, wide-field surveys have uncovered a group of extremely luminous optical transients. The initial discoveries SN 2005ap the Texas Supernova Search and SCP-06F6 in deep Hubble pencil beam survey were followed Palomar Transient Factory confirmation host redshifts for other similar transients share common properties high luminosities (peak magnitudes ∼−21 to −23), blue colors, lack H or He spectral features. physical mechanism that produces luminosity is uncertain,...
We present the Pan-STARRS1 discovery of long-lived and blue transient PS1-11af, which was also detected by Galaxy Evolution Explorer with coordinated observations in near-ultraviolet (NUV) band. PS1-11af is associated nucleus an early type galaxy at redshift z = 0.4046 that exhibits no evidence for star formation or active galactic activity. Four epochs spectroscopy reveal a pair broad absorption features UV on otherwise featureless spectra. Despite superficial similarity these to P-Cygni...
We present two luminous UV/optical flares from the nuclei of apparently inactive early-type galaxies at z = 0.37 and 0.33 that have radiative properties a flare tidal disruption star. In this paper we report second candidate event discovery in UV by GALEX Deep Imaging Survey simultaneous optical light curves CFHTLS for both flares. The first few months are well fitted with canonical t−5/3 power-law decay predicted emission fallback debris tidally disrupted Chandra ACIS X-ray observations...
We present the discovery of two ultra-luminous supernovae (SNe) at z ~ 0.9 with Pan-STARRS1 Medium-Deep Survey. These SNe, PS1-10ky and PS1-10awh, are amongst most luminous SNe ever discovered, comparable to unusual transients SN 2005ap SCP 06F6. Like 06F6, they show characteristic high luminosities (M_bol -22.5 mag), blue spectra a few broad absorption lines, no evidence for H or He. have constructed full multi-color light curve sensitive peak spectral energy distribution in rest-frame...
A dormant supermassive black hole lurking in the center of a galaxy will be revealed when star passes close enough to torn apart by tidal forces, and flare electromagnetic radiation is emitted bound fraction stellar debris falls back onto accreted. Although disruption rare event galaxy, ≈10−4 yr−1, observational candidates have emerged all-sky X-ray deep ultraviolet (UV) surveys form luminous UV/X-ray flares from otherwise quiescent galaxies. Here we present third candidate discovered Galaxy...
We report the discovery by intermediate Palomar Transient Factory (iPTF) of a candidate tidal disruption event (TDE) iPTF16axa at $z=0.108$, and present its broadband photometric spectroscopic evolution from 3 months follow-up observations with ground-based telescopes Swift. The light curve is well fitted $t^{-5/3}$ decay, we constrain rise-time to peak be $<$49 rest-frame days after disruption, which roughly consistent fallback timescale expected for $\sim 5\times$10$^{6}$ $M_\odot$ black...
The mass of the central black hole in a galaxy that hosted tidal disruption event (TDE) is an important parameter understanding its energetics and dynamics.We present first homogeneously measured masses complete sample 12 optically/UV-selected TDE host galaxies (down to g ≤ 22 mag z = 0.37) Northern sky.The estimates are based on velocity dispersion measurements, performed late time optical spectroscopic observations.We find range 3 × 10 5 M BH 2 7 .The dominated by low-mass holes (∼ 6 ), as...