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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…
LOFAR properties of SILVERRUSH Lyα emitter candidates in the ELAIS-N1 field
Bondi, M.; Prandoni, I.; Wang, L. +12 more
Lyman alpha emitters (LAEs) in the Epoch of Reionization (EoR) offer valuable probes of both early galaxy evolution and the process of reionization itself; however, the exact evolution of their abundance and the nature of their emission remain open questions. We combine samples of 229 and 349 LAE candidates at z = 5.7 and z = 6.6, respectively, fr…
Responses of the Indian Equatorial Ionization Anomaly to two CME-induced geomagnetic storms during the peak phase of solar cycle 24
Akala, A. O.; Oyedokun, O. J.; Simi, K. G. +4 more
This work analyzes the geo-effectiveness of Coronal Mass Ejection- (CME-) induced storms by investigating the responses of ionospheric Vertical Total Electron Content (VTEC) and the Equatorial Ionization Anomaly (EIA) over the Indian sector to two storms. One of the storms occurred on February 19, 2014 (SYM-H: -120 nT), while the other occurred on…
Improving the astrometric solution of the Hyper Suprime-Cam with anisotropic Gaussian processes
Rubin, D.; Astier, P.; Roodman, A. +5 more
Context. We study astrometric residuals from a simultaneous fit of Hyper Suprime-Cam images.
Aims: We aim to characterize these residuals and study the extent to which they are dominated by atmospheric contributions for bright sources.
Methods: We used Gaussian process interpolation with a correlation function (kernel) measured from the …
Gemini/Phoenix H-band analysis of the globular cluster AL 3
Minniti, D.; Zoccali, M.; Bica, E. +9 more
Context. The globular cluster AL 3 is old and located in the inner bulge. Three individual stars were observed with the Phoenix spectrograph at the Gemini South telescope. The wavelength region contains prominent lines of CN, OH, and CO, allowing the derivation of C, N, and O abundances of cool stars.
Aims: We aim to derive C, N, O abundances…
Principal Component Analysis for Estimating Parameters of the L1287 Dense Core by Fitting Model Spectral Maps into Observed Ones
Pirogov, L. E.; Zemlyanukha, P. M.
An algorithm has been developed for finding the global minimum of a multidimensional error function by fitting model spectral maps into observed ones. Principal component analysis is applied to reduce the dimensionality of the model and the coupling degree between the parameters, and to determine the region of the minimum. The k-nearest neighbors …
VEXAS: VISTA EXtension to Auxiliary Surveys. Data Release 2: Machine-learning based classification of sources in the Southern Hemisphere
Agnello, A.; Spiniello, C.; Khramtsov, V. +1 more
Context. We present the second public data release of the VISTA EXtension to Auxiliary Surveys (VEXAS), where we classify objects into stars, galaxies, and quasars based on an ensemble of machine learning algorithms.
Aims: The aim of VEXAS is to build the widest multi-wavelength catalogue, providing reference magnitudes, colours, and morpholo…