Search Publications
Do quasar X-ray and UV flux measurements provide a useful test of cosmological models?
Khadka, Narayan; Ratra, Bharat
The recent compilation of quasar (QSO) X-ray and ultraviolet (UV) flux measurements include QSOs that appear to not be standardizable via the X-ray luminosity and UV luminosity (LX-LUV) relation and so should not be used to constrain cosmological model parameters. Here, we show that the largest of seven sub-samples in this co…
Early Results from GLASS-JWST. VII. Evidence for Lensed, Gravitationally Bound Protoglobular Clusters at z = 4 in the Hubble Frontier Field A2744
Henry, Alaina; Zanella, A.; Vulcani, B. +29 more
We investigate the blue and optical rest-frame sizes (λ ≃ 2300-4000 Å) of three compact star-forming regions in a galaxy at z = 4 strongly lensed (×30, ×45, and ×100) by the Hubble Frontier Field galaxy cluster A2744 using GLASS-ERS James Webb Space Telescope (JWST)/NIRISS imaging at 1.15 µm, 1.50 µm, and 2.0 µm with a point-spre…
The observed multiplicity properties of B-type stars in the Galactic young open cluster NGC 6231
Evans, C. J.; Sana, H.; Mahy, L. +3 more
Context. It is well known that massive O stars are frequently (if not always) found in binary or higher-order multiple systems, but this fact has been less robustly investigated for the lower mass range of the massive stars, represented by B-type stars. Obtaining the binary fraction and orbital parameter distributions of B-type stars is crucial to…
The DECam Local Volume Exploration Survey Data Release 2
Bacon, D.; Bechtol, K.; Smith, M. +125 more
We present the second public data release (DR2) from the DECam Local Volume Exploration survey (DELVE). DELVE DR2 combines new DECam observations with archival DECam data from the Dark Energy Survey, the DECam Legacy Survey, and other DECam community programs. DELVE DR2 consists of ~160,000 exposures that cover >21,000 deg2 of the hi…
Identifying quiescent compact objects in massive Galactic single-lined spectroscopic binaries
Shenar, T.; Sana, H.; Hawcroft, C. +13 more
Context. The quest to detect dormant stellar-mass black holes (BHs) in massive binaries (i.e. OB+BH systems) is challenging; only a few candidates have been claimed to date, all of which must still be confirmed.
Aims: To search for these rare objects, we study 32 Galactic O-type stars that were reported as single-lined spectroscopic binaries …
The Warm Neptune GJ 3470b Has a Polar Orbit
Cochran, William D.; Endl, Michael; Mahadevan, Suvrath +34 more
The warm Neptune GJ 3470b transits a nearby (d = 29 pc) bright slowly rotating M1.5-dwarf star. Using spectroscopic observations during two transits with the newly commissioned NEID spectrometer on the WIYN 3.5 m Telescope at Kitt Peak Observatory, we model the classical Rossiter-McLaughlin effect, yielding a sky-projected obliquity of $\lambda ={…
An Improved Calibration of the Wavelength Dependence of Metallicity on the Cepheid Leavitt Law
Riess, Adam G.; Breuval, Louise; Anderson, Richard I. +2 more
The Cepheid period-luminosity (PL) relation (or Leavitt law) has served as the first rung of the most widely used extragalactic distance ladder and is central to the determination of the local value of the Hubble constant (H 0). We investigate the influence of metallicity on Cepheid brightness, a term that significantly improves the ove…
KiDS and Euclid: Cosmological implications of a pseudo angular power spectrum analysis of KiDS-1000 cosmic shear tomography
Cimatti, A.; Douspis, M.; Dupac, X. +111 more
We present a tomographic weak lensing analysis of the Kilo Degree Survey Data Release 4 (KiDS-1000), using a new pseudo angular power spectrum estimator (pseudo-Cℓ) under development for the ESA Euclid mission. Over 21 million galaxies with shape information are divided into five tomographic redshift bins, ranging from 0.1 to 1.2 in pho…
AGN Selection and Demographics in GOODS-S/HUDF from X-Ray to Radio
Lyu, Jianwei; Rieke, George H.; Alberts, Stacey +1 more
We present a comprehensive census of the active galactic nuclei (AGNs) in the GOODS-S/HUDF region from the X-ray to the radio, covering both the obscured and unobscured populations. This work includes a robust analysis of the source optical to mid-IR spectral energy distributions (SEDs) featuring (semi)empirical AGN and galaxy dust emission models…
Parameter estimation with gravitational waves
Christensen, Nelson; Meyer, Renate
The new era of gravitational wave astronomy truly began on September 14, 2015, with the detection of GW150914, the sensational first direct observation of gravitational waves from the inspiral and merger of two black holes by the two Advanced LIGO detectors. In the subsequent first three observing runs of the LIGO-Virgo network, gravitational wave…