Search Publications
Optically detected galaxy cluster candidates in the AKARI North Ecliptic Pole field based on photometric redshift from the Subaru Hyper Suprime-Cam
Hashimoto, Tetsuya; Goto, Tomotsugu; Kim, Seong Jin +23 more
Galaxy clusters provide an excellent probe in various research fields in astrophysics and cosmology. However, the number of galaxy clusters detected so far in the AKARI North Ecliptic Pole (NEP) field is limited. In this work, we provide galaxy cluster candidates in the AKARI NEP field with the minimum requisites based only on the coordinates and …
Mapping Gaia Parallax Systematic Errors over the Sky with Faint Milky Way Stars
Fardal, Mark A.; Sohn, Sangmo Tony; del Pino, Andrés +1 more
Parallaxes measured by the Gaia mission have huge significance for astronomy, but parallaxes in Gaia DR2 are known to have systematic errors that depend on the source position and other quantities. We use the abundant information in faint Milky Way stars, along with the Gaia Object Generator simulation of the Gaia catalog, to probe the spatial dep…
X-ray obscuration from a variable ionized absorber in PG 1114+445
Piconcelli, E.; Gaspari, M.; Tombesi, F. +9 more
Photoionized absorbers of outflowing gas are commonly found in the X-ray spectra of active galactic nuclei. While most of these absorbers are seldom significantly variable, some ionized obscurers have increasingly been found to substantially change their column density on a wide range of timescales. These NH variations are often conside…
Chandra Observations of Abell 2261 Brightest Cluster Galaxy, a Candidate Host to a Recoiling Black Hole
Lauer, Tod R.; Ogle, Patrick; Postman, Marc +4 more
We use Chandra X-ray observations to look for evidence of a recoiling black hole from the brightest cluster galaxy in Abell 2261 (A2261-BCG). A2261-BCG is a strong candidate for a recoiling black hole because of its large, flat stellar core, revealed by Hubble Space Telescope imaging observations. We took 100 ks observations with Chandra and combi…
Two Luminous Post-AGB Stars in the Galactic Globular Cluster M19
Bond, Howard E.; Ciardullo, Robin; Siegel, Michael H. +1 more
We report the discovery of a luminous "yellow" post-asymptotic giant branch (PAGB) star in the globular cluster (GC) M19 (NGC 6273), identified during our uBVI survey of Galactic GCs. The uBVI photometric system is optimized to detect stars with large Balmer discontinuities, indicating very low surface gravities and high luminosities. The spectral…
Planets around young active solar-type stars: assessing detection capabilities from a non-stabilized spectrograph
Petit, P.; Wittenmyer, R. A.; Heitzmann, A. +8 more
Short-orbit gas giant planet formation/evolution mechanisms are still not well understood. One promising pathway to discriminate between mechanisms is to constrain the occurrence rate of these peculiar exoplanets at the earliest stage of the system's life. However, a major limitation when studying newly born stars is stellar activity. This cocktai…
A novel survey for young substellar objects with the W-band filter III: Searching for very low-mass brown dwarfs in Serpens South and Serpens Core
Jose, Jessy; Allers, Katelyn; Albert, Loïc +10 more
We present CFHT photometry and IRTF spectroscopy of low-mass candidate members of Serpens South and Serpens Core (~430 pc, ~0.5 Myr), identified using a novel combination of photometric filters, known as the W-band method. We report SC182952+011618, SS182959-020335, and SS183032-021028 as young, low-mass Serpens candidate members, with spectral ty…
A MeerKAT 1.28 GHz Atlas of Southern Sources in the IRAS Revised Bright Galaxy Sample
Marchetti, L.; Jarrett, T.; Moloko, M. E. +4 more
The IRAS Revised Bright Galaxy Sample (RBGS) comprises galaxies and unresolved mergers stronger than S = 5.24 Jy at λ = 60 µm with Galactic latitudes ∣b∣ > 5°. Nearly all are dusty star-forming galaxies whose radio continuum and far-infrared luminosities are proportional to their current rates of star formation. We used the MeerKAT array …
Radiative Transfer Modeling of an SN 1987A Light Echo-AT 2019xis
Wang, Lifan; Brown, Peter; Ding, Jiachen +1 more
We use a Monte Carlo radiative transfer model (MCRTM) to simulate the UBVRI light curves, images, and linear polarization of a light echo from supernova SN 1987A in the Large Magellanic Cloud (LMC) using various dust cloud shapes, sizes, and optical properties. We compare the theoretical simulations to the observations of AT 2019xis, a light echo …
Comprehensive broad-band study of accreting neutron stars with Suzaku: Is there a bi-modality in the X-ray spectrum?
Maitra, Chandreyee; Paul, Biswajit; Pradhan, Pragati +2 more
We present a broad-band spectral analysis of accreting neutron stars using data from XIS and PIN onboard Suzaku. From spectral fits of these sources with a single continuum model including a power law and high energy cut-off, cyclotron lines (where required), we studied the correlation between various spectral parameters. Among 39 sources we studi…