We present and validate 20 deg$^2$ of overlapping synthetic imaging surveys representing the full depth of the Nancy Grace Roman Space Telescope High-Latitude Imaging Survey (HLIS) and five years of observations of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). The two synthetic surveys are summarized, with reference to the existing 300 deg$^2$ of LSST simulated imaging produced as part of Dark Energy Science Collaboration (DESC) Data Challenge 2 (DC2). Both synthetic surveys observe the same simulated DESC DC2 universe. For the synthetic Roman survey, we simulate for the first time fully chromatic images along with the detailed physics of the Sensor Chip Assemblies derived from lab measurements using the flight detectors. The simulated imaging and resulting pixel-level measurements of photometric properties of objects span a wavelength range of $\sim$0.3 to 2.0 $\mu$m. We also describe updates to the Roman simulation pipeline, changes in how astrophysical objects are simulated relative to the original DC2 simulations, and the resulting simulated Roman data products. We use these simulations to explore the relative fraction of unrecognized blends in LSST images, finding that 20-30% of objects identified in LSST images with $i$-band magnitudes brighter than 25 can be identified as multiple objects in Roman images. These simulations provide a unique testing ground for the development and validation of joint pixel-level analysis techniques of ground- and space-based imaging data sets in the second half of the 2020s -- in particular the case of joint Roman--LSST analyses.
29 pages, 15 figures, 1-2 black holes. Submitted to MNRAS
We report discovery of a bright, nearby ($G = 13.8$; $d = 480$ pc) Sun-like star orbiting a dark object. We identified the system as a black hole candidate via its astrometric orbital solution from the Gaia mission. Radial velocity monitoring validated and refined the Gaia solution, and spectroscopy ruled out significant light contributions from another star. Joint modeling of radial velocities and astrometry constrains the companion mass to $M_2 = 9.8\pm 0.2\,M_{\odot}$. The spectroscopic orbit alone sets a minimum companion mass of $M_2>5\,M_{\odot}$; if the companion were a $5\,M_{\odot}$ star, it would be 500 times more luminous than the entire system. These constraints are insensitive to the assumed mass of the luminous star, which appears as a slowly-rotating G dwarf ($T_{\rm eff}=5850$ K, $\log g = 4.5$, $M=0.93\,M_{\odot}$), with near-solar metallicity ([Fe/H] = -0.2) and an unremarkable abundance pattern. We find no plausible astrophysical scenario that can explain the orbit and does not involve a black hole. The orbital period, $P_{\rm orb}=185.6$ days, is longer than that of any known stellar-mass black hole binary, and the eccentricity is modest, $e=0.45$. The system's Galactic orbit is typical of thin-disk stars, suggesting that it formed in the Milky Way disk with at most a weak natal kick. Explaining the system's formation with standard binary evolutionary models is challenging: it is difficult for the luminous star to survive a common envelope event under standard assumptions, and difficult for it to end up in a wide orbit afterward. Formation models involving triples or dynamical assembly in an open cluster may be more promising. This is the nearest known black hole by a factor of 3, and its discovery suggests the existence of a sizable population of dormant black holes in binaries. Future Gaia releases will likely facilitate the discovery of dozens more.
21 pages, submitted to ApJ
Mass measurements from low-mass black hole X-ray binaries (LMXBs) and radio pulsars have been used to identify a gap between the most massive neutron stars (NS) and the least massive black holes (BH). BH mass measurements in LMXBs are typically only possible for transient systems: outburst periods enable detection via all-sky X-ray monitors, while quiescent periods enable radial-velocity measurements of the low-mass donor. We present the first quantitative study of selection biases due to the requirement of transient behavior for BH mass measurements. Using rapid population synthesis simulations (COSMIC), detailed binary stellar-evolution models (MESA), and the disk instability model of transient behavior, we demonstrate that transient LMXB selection effects do introduce biases into the observed sample. If a gap is not inherent in BH birth masses, mass growth through LMXB accretion and selection effects can suppress mass-gap BHs in the observed sample. Our results are robust against variations of binary evolution prescriptions. We further find that a population of transient LMXBs with mass-gap BHs form through accretion induced collapse of a NS during the LMXB phase. The significance of this population is dependent on the maximum NS birth mass $M_\mathrm{NS, birth-max}$. For $M_\mathrm{NS, birth-max}=3M_{\odot}$, MESA and COSMIC models predict a similar fraction of mass gap LMXBs. However, for $M_\mathrm{NS, birth-max}\lesssim2M_{\odot}$ and realistic models of the disk-instability, our MESA models produce a dearth of mass-gap LMXBs, more consistent with observations. This constraint on $M_\mathrm{NS, birth-max}$ is independent of whether low-mass BHs form at core-collapse.
Submitted for publication in MNRAS. 9 pages, 4 figures
17 pages, 10 figures, submitted to ApJ
22 pages, 14 figures, to be submitted to MNRAS. Contact: lovell@hi.is
8 pages, 4 figures. Analysis of early release JWST data. Submitted to MNRAS. Comments welcome
Submitted to MNRAS
25 pages, 11 figures, summary video: this https URL
Accepted in ApJL
10 pages, accepted for publication in MNRAS
21 pages, 18 figures
34 pages, 12 figures, submitted to ApJ
17 pages, 14 figures (1 appendix for galaxy examples including 3 figures)
10 pages, 6 figures. Accepted for publication on MNRAS
Submission pre-referee report
22 pages, 23 pages, accepted for publication in A&A (18 August 2022)
33 pages, 13 figures; submitted to ApJ
A&A accepted. 15 pages, 18 figures
18 pages including appendices. Zenodo repo will be populated with arxiv v2 at latest
13 pages, 5 figures, accepted for publication in ApJ
10 pages, 5 figures
8 pages, 5 Figures, accepted for publication in ApJL (Astrophysical Journal Letters)
22 pages, 13 figures, accepted for publication in Astronomy & Astrophysics
20 pages, 10 figures, accepted for publication in The Astrophysical Journal
4 pages, 4 figures
Accepted for publication in ApJ Letters
Accepted for publication in SPIE Astronomical Telescope and Instrumentation Conference proceedings - Montreal (Canada) July 2022
arXiv admin note: text overlap with arXiv:2012.12693
Accepted for publication in SPIE Astronomical Telescope and Instrumentation Conference proceedings (Montreal, Canada July 2022)
accepted for ApJ Letters
Accepted for publication in SPIE Astronomical Telescopes and Instrumentation conference proceedings (Montreal, Canada July 2022)
16 pages, 10 figures
Accepted for publication in ApJ, 26 pages, 13 figures, 6 tables
Proc. SPIE 12184, Ground-based and Airborne Instrumentation for Astronomy IX, 121840O (2022)
10 pages, 7 figures, published in SPIE proceedings volume 12189. arXiv admin note: substantial text overlap with arXiv:2012.12678
22 pages, 15 figures, accepted by ApJ
8 pages, 8 figures, SPIE conference proceeding
6 pages, 8 Figures, SPIE: Astronomical Telescope + Instrumentation, Montreal 2022
12 pages, 6 figures, SPIE proceedings of the conference Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV
12 pages, 4 Figures, SPIE: Astronomical Telescope + Instrumentation, Montreal 2022. arXiv admin note: text overlap with arXiv:1812.07401
13 pages, 13 figures, submitted to MNRAS
21 pages, 4 figures, comments welcome
22 pages, 9 figures, Accepted for publication in The Astrophysical Journal
18 pages, 15 figures. Accepted for publication (MNRAS)
27 pages, 10 figures; accepted for publication in ApJ
Accepted in Proceedings of the International Astronomical Union, Volume 15 Issue 363
SPIE proceedings, SPIE Astronomical Telescopes + Instrumentation 2022, Montr\'eal, Canada
Book chapter for the "Handbook of X-ray and Gamma-ray Astrophysics", Section "Optics and Detectors for Gamma-ray Astrophysics" (Editors in chief: C. Bambi and A. Santangelo, Springer Singapore). 39 pages, 16 figures
12 pages, 4 figures, submitted to the Astrophysical Journal Letters
Published in JOSS. Git repo is available at this https URL
6 pages, 2 figures, 1 table
12 Pages, 5 figures
9 pages, 10 figures
Submitted to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021) under Cosmic Frontier (CF07: Cosmic probes of fundamental physics); 30 pages, 8 figures
16 Pages, 12 Figures
17 pages, 10 figures, published in SPIE
Writeup of a talk given at SPIE Astronomical Telescopes + Instrumentation, 2022, Montreal, Quebec, Canada. arXiv admin note: text overlap with arXiv:1612.06415
13 pages, 5 figures, SPIE conference proceedings
20 pages + appendix and bibliography (26 pages total); 11 figures, 1 table; to be submitted to PRD
9 pages, 6 figures, submitted to ApJ
9 pages, 2 figures
57 pages
13 pages. 9 figures. Submitted to Phys. Rev. D
30 pages, 4 figures, 4 tables; comments are welcome
19 pages with no figures, comments are very welcome !
Submitted 30 pages, 11 figures, many references, Report of the CF1 Topical Group for Snowmass 2021
42 pages, 5 figures