Search Publications
Jet Parameters in the Black Hole X-Ray Binary MAXI J1820+070
Zdziarski, Andrzej A.; Sikora, Marek; Tetarenko, Alexandra J.
We study the jet in the hard state of the accreting black hole (BH) binary MAXI J1820+070. From the available radio-to-optical spectral and variability data, we put strong constraints on the jet parameters. We find while it is not possible to uniquely determine the jet Lorentz factor from the spectral and variability properties alone, we can estim…
Investigating the Nature of the Luminous Ambiguous Nuclear Transient ASASSN-17jz
Filippenko, Alexei V.; Burgasser, Adam J.; Im, Myungshin +31 more
We present observations of the extremely luminous but ambiguous nuclear transient (ANT) ASASSN-17jz, spanning roughly 1200 days of the object's evolution. ASASSN-17jz was discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) in the galaxy SDSS J171955.84+414049.4 on UT 2017 July 27 at a redshift of z = 0.1641. The transient peaked at…
z 2-9 Galaxies Magnified by the Hubble Frontier Field Clusters. I. Source Selection and Surface Density-Magnification Constraints from >2500 Galaxies
Bouwens, R. J.; Oesch, P.; Illingworth, G. +4 more
We assemble a large comprehensive sample of 2534 z ~ 2, 3, 4, 5, 6, 7, 8, and 9 galaxies lensed by the six clusters from the Hubble Frontier Fields (HFF) program. Making use of the availability of multiple independent magnification models for each of the HFF clusters and alternatively treating one of the models as the "truth," we show that the med…
The Hough Stream Spotter: A New Method for Detecting Linear Structure in Resolved Stars and Application to the Stellar Halo of M31
Williams, Benjamin F.; Ness, Melissa K.; Ibata, Rodrigo A. +5 more
Stellar streams from globular clusters (GCs) offer constraints on the nature of dark matter and have been used to explore the dark matter halo structure and substructure of our Galaxy. Detection of GC streams in other galaxies would broaden this endeavor to a cosmological context, yet no such streams have been detected to date. To enable such expl…
SpinSpotter : An Automated Algorithm for Identifying Stellar Rotation Periods with Autocorrelation Analysis
Hartigan, Patrick; Oelkers, Ryan J.; Robertson, Paul +2 more
SpinSpotter is a robust and automated algorithm designed to extract stellar rotation periods from large photometric data sets with minimal supervision. Our approach uses the autocorrelation function (ACF) to identify stellar rotation periods up to one-third the observational baseline of the data. Our algorithm also provides a suite of diagnostics …
The Mass Scale of High-redshift Galaxies: Virial Mass Estimates Calibrated with Stellar Dynamical Models from LEGA-C
Bell, Eric F.; Maseda, Michael V.; D'Eugenio, Francesco +9 more
Dynamical models for 673 galaxies at z = 0.6-1.0 with spatially resolved (long-slit) stellar kinematic data from LEGA-C are used to calibrate virial mass estimates defined as ${M}_{\mathrm{vir}}=K\sigma {{\prime} }_{\star ,\mathrm{int}}^{2}R$ , with K a scaling factor, $\sigma {{\prime} }_{\star ,\mathrm{int}}$ the spatially integrated stellar vel…
On the Nature of Ultracool White Dwarfs: Not so Cool after All
Bergeron, P.; Blouin, Simon; Kilic, Mukremin +3 more
A recent analysis of the 100 pc white dwarf sample in the SDSS footprint demonstrated for the first time the existence of a well-defined ultracool-or IR-faint-white dwarf sequence in the Hertzsprung-Russell diagram. Here we take advantage of this discovery to enlarge the IR-faint white dwarf sample threefold. We expand our selection to the entire …
The Space Density of Ultra-luminous QSOs at the End of Reionization Epoch by the QUBRICS Survey and the AGN Contribution to the Hydrogen Ionizing Background
Grazian, Andrea; Boutsia, Konstantina; Cupani, Guido +6 more
Motivated by evidences favoring a rapid and late hydrogen reionization process completing at z ~ 5.2-5.5 and mainly driven by rare and luminous sources, we have reassessed the estimate of the space density of ultra-luminous QSOs at z ~ 5 in the framework of the QUBRICS survey. A ~ 90% complete sample of 14 spectroscopically confirmed QSOs at M
Orbital Decay in M82 X-2
Israel, Gian Luca; Fürst, Felix; Wilms, Jörn +21 more
M82 X-2 is the first pulsating ultraluminous X-ray source discovered. The luminosity of these extreme pulsars, if isotropic, implies an extreme mass transfer rate. An alternative is to assume a much lower mass transfer rate, but with an apparent luminosity boosted by geometrical beaming. Only an independent measurement of the mass transfer rate ca…
The Mass-Metallicity Relation at Cosmic Noon in Overdense Environments: First Results from the MAMMOTH-Grism HST Slitless Spectroscopic Survey
Teplitz, Harry I.; Fan, Xiaohui; Cai, Zheng +9 more
The MAMMOTH-Grism slitless spectroscopic survey is a Hubble Space Telescope (HST) cycle 28 medium program, which is obtaining 45 orbits of WFC3/IR grism spectroscopy in the density peak regions of three massive galaxy protoclusters at z = 2-3 discovered using the MAMMOTH technique. We introduce this survey by presenting the first measurement of th…