A5062465222- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- SAS software applications and methods
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Particle Accelerators and Free-Electron Lasers
- Adaptive optics and wavefront sensing
- Advanced X-ray and CT Imaging
- Particle Detector Development and Performance
- Radiation Dose and Imaging
- Water Quality Monitoring and Analysis
- GNSS positioning and interference
- Microbial Metabolites in Food Biotechnology
- Advanced Power Generation Technologies
- Superconducting and THz Device Technology
Center for Astrophysics Harvard & Smithsonian
2015-2024
The NSF AI Institute for Artificial Intelligence and Fundamental Interactions
2021-2024
Community Farm Alliance
2009-2021
Harvard University Press
2011-2020
Harvard College Observatory
2020
Harvard University
2009-2019
University of Geneva
2016
Instituto de Astrofísica de Andalucía
2016
Smithsonian Astrophysical Observatory
2010
Princeton University
2005-2009
We present optical light curves, redshifts, and classifications for 365 spectroscopically confirmed Type Ia supernovae (SNe Ia) discovered by the Pan-STARRS1 (PS1) Medium Deep Survey. detail improvements to PS1 SN photometry, astrometry calibration that reduce systematic uncertainties in distances. combine subset of 279 ($0.03 < z 0.68$) with useful distance estimates from SDSS, SNLS, various low-z HST samples form largest combined sample consisting a total 1048 ranging $0.01 2.3$, which we...
We present a comprehensive sample of all gamma-ray burst (GRB) afterglows with known distances, and we derive their conical opening angles based on observed broadband breaks in light curves. Within the framework this jet model, correct for geometry find that energy release is narrowly clustered around 5 × 1050 ergs. draw three conclusions. First, central engines GRBs energies are comparable to ordinary supernovae. Second, broad distribution fluence luminosity largely result wide variation...
We present UV, optical, and NIR photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced LIGO/Virgo, binary neutron star merger GW170817. Our data set extends discovery optical at $0.47$ days $18.5$ post-merger, includes observations with Dark Energy Camera (DECam), Gemini-South/FLAMINGOS-2 (GS/F2), {\it Hubble Space Telescope} ({\it HST}). The spectral energy distribution (SED) inferred this $0.6$ is well described by blackbody model $T\approx 8300$...
Gamma-ray bursts (GRBs) display a bimodal duration distribution with separation between the short- and long-duration at about 2 s. The progenitors of long GRBs have been identified as massive stars based on their association Type Ic core-collapse supernovae (SNe), exclusive location in star-forming galaxies, strong correlation bright UV regions within host galaxies. Short suspected theoretical grounds to arise from compact object binary mergers (neutron star–neutron star or neutron...
We use gravitational-wave observations of the binary neutron star merger GW170817 to explore tidal deformabilities and radii stars. perform a Bayesian parameter estimation with source location distance informed by electromagnetic observations. also assume that two stars have same equation state; we demonstrate that, for masses comparable component GW170817, this is effectively implemented assuming stars' dimensionless are determined binary's mass ratio q Λ_{1}/Λ_{2}=q^{6}. investigate...
Abstract We present the Dark Energy Camera (DECam) discovery of optical counterpart first binary neutron star merger detected through gravitational-wave emission, GW170817. Our observations commenced 10.5 hr post-merger, as soon localization region became accessible from Chile. imaged 70 deg 2 in i and z bands, covering 93% initial integrated probability, to a depth necessary identify likely counterparts (e.g., kilonova). At 11.4 post-merger we bright transient located nucleus NGC 4993 at...
The Very Large Array Sky Survey (VLASS) is a synoptic, all-sky radio sky survey with unique combination of high angular resolution ($\approx$2.5"), sensitivity (a 1$\sigma$ goal 70 $\mu$Jy/beam in the coadded data), full linear Stokes polarimetry, time domain coverage, and wide bandwidth (2-4 GHz). first observations began September 2017, observing for will finish 2024. VLASS use approximately 5500 hours on Karl G. Jansky (VLA) to cover whole visible VLA (Declination $>-40^{\circ}$), total...
We present the science case, reference design, and project plan for Stage-4 ground-based cosmic microwave background experiment CMB-S4.
We present a comprehensive catalog and analysis of broadband afterglow observations for 103 short-duration gamma-ray bursts (GRBs), comprised all short GRBs from 2004 November to 2015 March with prompt follow-up in the X-ray, optical, near-infrared (NIR), and/or radio bands. These have uncovered 71 X-ray detections, 30 optical/NIR 4 detections. Employing standard synchrotron model, we perform joint probability analyses subset 38 well-sampled light curves infer burst isotropic-equivalent...
Gamma-ray bursts (GRBs) serve as powerful probes of the early Universe, with their luminous afterglows revealing locations and physical properties star forming galaxies at highest redshifts, potentially locating first generation (Population III) stars. Since GRB have intrinsically very simple spectra, they allow robust redshifts from low signal to noise spectroscopy, or photometry. Here we present a photometric redshift z~9.4 for Swift-detected 090429B based on deep observations...
We report the discovery of rising X-ray emission from binary neutron star (BNS) merger event GW170817. This is first detection a gravitational-wave source. Observations acquired with Chandra Observatory (CXO) at t~2.3 days post reveal no significant emission, L_x<=3.2x10^38 erg/s (isotropic-equivalent). Continued monitoring revealed presence an source that brightened time, reaching L_x\sim 9x10^39 ~15.1 merger. interpret these findings in context isotropic and collimated relativistic...
We present Very Large Array (VLA) and Atacama Millimeter/sub-millimeter ALMA radio observations of GW\,170817, the first Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo gravitational wave (GW) event from a binary neutron star merger GW with an electromagnetic (EM) counterpart. Our data include following discovery optical transient at both centimeter ($13.7$ hours post merger) millimeter ($2.41$ days bands. detect faint emission 6 GHz 19.47 39.23 after merger, but not in...
We present a near-infrared spectral sequence of the electromagnetic counterpart to binary neutron star merger GW170817 detected by Advanced LIGO/Virgo. Our dataset comprises seven epochs J+H spectra taken with FLAMINGOS-2 on Gemini-South between 1.5 and 10.5 days after merger. In initial epoch, spectrum is dominated smooth blue continuum due high-velocity, lanthanide-poor kilonova component. Starting following night, all subsequent instead show features that are similar those predicted in...
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...
We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations several thousand seconds. demonstrate that these events are extragalactic transients; in particular we resolve the long-standing conundrum distance GRB 101225A (the "Christmas-day burst"), finding it to have a redshift z=0.847, and showing two apparently similar (GRB 111209A 121027A) lie at z=0.677 z=1.773 respectively. The systems show extremely unusual X-ray optical lightcurves, very...
Abstract We present the first effort to aggregate, homogenize, and uniformly model combined ultraviolet, optical, near-infrared data set for electromagnetic counterpart of binary neutron star merger GW170817. By assembling all available from 18 different papers 46 instruments, we are able identify mitigate systematic offsets between individual sets clear outlying measurements, with resulting pruned adjusted offering an opportunity expand study kilonova. The unified includes 647 flux spanning...
Abstract We present optical and ultraviolet spectra of the first electromagnetic counterpart to a gravitational-wave (GW) source, binary neutron star merger GW170817. Spectra were obtained nightly between 1.5 9.5 days post-merger, using Southern Astrophysical Research Magellan telescopes; UV spectrum was with Hubble Space Telescope at 5.5 days. Our data reveal rapidly fading blue component ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>T</mml:mi>...
We present optical spectroscopy and optical/near-IR photometry of 31 host galaxies hydrogen-poor superluminous supernovae (SLSNe), including 15 events from the Pan-STARRS1 Medium Deep Survey. Our sample spans redshift range 0.1 ≲ z 1.6, is first comprehensive galaxy study this specific subclass cosmic explosions. Combining multi-band emission-line measurements, we determine luminosities, stellar masses, star formation rates, metallicities. find that, as a whole, hosts SLSNe are...