Search Publications
The ASAS-SN catalogue of variable stars - IV. Periodic variables in the APOGEE survey
Kochanek, C. S.; Stanek, K. Z.; Thompson, Todd A. +12 more
We explore the synergy between photometric and spectroscopic surveys by searching for periodic variable stars among the targets observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) using photometry from the All-Sky Automated Survey for Supernovae (ASAS-SN). We identified 1924 periodic variables among more than 258 000 AP…
Investigating the X-ray enhancements of highly radio-loud quasars at z > 4
Brandt, W. N.; Garmire, G. P.; Miller, B. P. +2 more
We have investigated the jet-linked X-ray emission from highly radio-loud quasars (HRLQs; log R > 2.5) at high redshift. We studied the X-ray properties of 15 HRLQs at z > 4, using new Chandra observations for six objects and archival XMM-Newton and Swift observations for the other nine. We focused on testing the apparent enhancement of jet-…
Astrometric and photometric study of NGC 6067, NGC 2506, and IC 4651 open clusters based on wide-field ground and Gaia DR2 data
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +2 more
We present an analysis of three southern open star clusters NGC 6067, NGC 2506, and IC 4651 using wide-field photometric and Gaia DR2 astrometric data. They are poorly studied clusters. We took advantage of the synergy between Gaia DR2 high precision astrometric measurements and ground-based wide-field photometry to isolate cluster members and fur…
X-ray properties of z > 4 blazars
Moretti, A.; Ballo, L.; Dallacasa, D. +4 more
We present the X-ray analysis of the largest flux-limited complete sample of blazar candidates at z > 4 selected from the Cosmic Lens All Sky Survey (CLASS). After obtaining a nearly complete (24/25) X-ray coverage of the sample (from Swift-XRT, XMM-Newton, and Chandra), we analysed the spectra in order to identify the bona fide blazars. We cla…
Accounting for multiplicity in calculating eta Earth
Zink, Jon K.; Hansen, Bradley M. S.
Using the updated exoplanet population parameters of our previous study, which includes the planetary radius updates from Gaia DR2 and an inferred multiplicity distribution, we provide a revised η⊕ calculation. This is achieved by sampling planets from our derived population model and determining which planets meet our criterion for hab…
The stellar initial mass function of the solar neighbourhood revealed by Gaia
Sollima, A.
I use a sample of more than 120 000 stars in the solar neighbourhood, with parallaxes, magnitudes and colours estimated with unprecedented accuracy by the second data release of the Gaia mission, to derive the initial mass function of the Galactic disc. A full-forward technique is used to take into account, for the population of unresolved binarie…
Expected intermediate-mass black holes in the Virgo cluster - II. Late-type galaxies
Soria, Roberto; Graham, Alister W.; Davis, Benjamin L.
The Chandra X-ray Observatory's Cycle 18 Large Program titled `Spiral galaxies of the Virgo Cluster' will image 52 galaxies with the ACIS-S detector. Combined with archival data for an additional 22 galaxies, this will represent the complete sample of 74 spiral galaxies in the Virgo cluster with star formation rates ≳0.3 M⊙ yr-1
The AGN fuelling/feedback cycle in nearby radio galaxies - II. Kinematics of the molecular gas
Davis, Timothy A.; Bureau, Martin; Casasola, Viviana +7 more
This is the second paper of a series exploring the multicomponent (stars, warm and cold gas, and radio jets) properties of a sample of 11 nearby low-excitation radio galaxies, with the aim of better understanding the active galactic nuclei (AGN) fuelling/feedback cycle in these objects. Here, we present a study of the molecular gas kinematics of s…
An observational test for star formation prescriptions in cosmological hydrodynamical simulations
Buck, Tobias; Dutton, Aaron A.; Macciò, Andrea V.
State-of-the-art cosmological hydrodynamical simulations of galaxy formation have reached the point at which their outcomes result in galaxies with ever more realism. Still, the employed sub-grid models include several free parameters such as the density threshold, n, to localize the star-forming gas. In this work, we investigate the possibilities…
An extreme amplitude, massive heartbeat system in the LMC characterized using ASAS-SN and TESS
Kochanek, C. S.; Stanek, K. Z.; Thompson, Todd A. +3 more
Using ASAS-SN data, we find that the bright (V∼ 13.5 mag) variable star MACHO 80.7443.1718 (ASASSN-V J052624.38-684705.6) is the most extreme heartbeat star yet discovered. This massive binary, consisting of at least one early B-type star, has an orbital period of P_ASAS-SN=32.83627± 0.00846 d, and is located towards the LH58 OB complex in the LMC…