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High-precision calculation of the light curve and its interpretation
Abubekerov, M. K.; Gostev, N. Yu.
We present a highly precise calculation of the theoretical light curve and its derivatives for a binary star-planet system in an elliptical orbit. We also describe an analytical fitting by limb-darkening coefficients to reduce the number of parameters for nonlinear fitting. We demonstrate the practical importance of the precision computation of th…
Chandra Imaging of the Western Hotspot in the Radio Galaxy Pictor A: Image Deconvolution and Variability Analysis
Cheung, C. C.; Stawarz, Ł.; Siemiginowska, A. +3 more
Here we present an analysis of the X-ray morphology and flux variability of the particularly bright and extended western hotspot in the nearest powerful (FR II-type) radio galaxy, Pictor A, based on data obtained with the Chandra X-ray Observatory. The hotspot marks the position where the relativistic jet, which originates in the active nucleus of…
Wolf-Rayet stars in M 81 using GTC/OSIRIS: seven new detections, analysis, and classification of the full sample
Alvarez, C.; Toalá, J. A.; Gómez-González, V. M. A. +3 more
We report the detection of seven new Wolf-Rayet (WR) star locations in M 81 using the Multi-Object Spectrograph of the OSIRIS instrument at Gran Telescopio Canarias. These detections are the result of a follow-up of an earlier study using the same instrumental set-up that resulted in the detection of 14 WR locations. We analyse the entire sample o…
An XMM-Newton X-Ray View of Supernova Remnant W49B: Revisiting Its Recombining Plasmas and Progenitor Type
Chen, Yang; Sun, Lei
We present a comprehensive X-ray spectroscopy and imaging study of supernova remnant W49B using archival XMM-Newton observations. The overionization state of the shocked ejecta in W49B is clearly indicated by the radiative recombination continua of Si XIV, S XV, and Fe XXV, combined with the Lyα lines of Ca and Fe. The line flux images of W49B ind…
Accretion-driven Sources in Spatially Resolved Lyα Emitters
Hayes, Matthew; Östlin, Göran; Melinder, Jens +4 more
Lyα emission is a standard tracer of starburst galaxies at high redshift. However, a number of local Lyα emitters (LAEs) are X-ray sources, suggesting a possible origin of Lyα photons other than young, hot stars, and which may be active at much later ages relative to the parent starburst. Resolved, nearby LAEs offer the opportunity to discriminate…
Direct Imaging Discovery of a Young Brown Dwarf Companion to an A2V Star
Currie, Thayne; Wagner, Kevin; Apai, Dániel +3 more
We present the discovery and spectroscopy of HIP 75056Ab, a companion directly imaged at a very small separation of 0"125 to an A2V star in the Scorpius-Centaurus OB2 association. Our observations utilized Very Large Telescope/Spectro-Polarimetric High-contrast Exoplanet Research Experiment between 2015 and 2019, enabling low-resolution spectrosco…
Understanding the physical properties of young M dwarfs: NIR spectroscopic studies
Mondal, Soumen; Das, Ramkrishna; Khata, Dhrimadri +2 more
We present here medium resolution (λ/Δλ ∼ 1200) H- and K-band spectra of M-type dwarf stars covering the wavelength ranges 1.50-1.80 µm and 1.95-2.45 µm. The sample includes 53 dwarf stars (M0V-M7V) from new observations using the TIFR Near-Infrared Spectrometer and Imager instrument on the 2-m Himalayan Chandra Telescope. Using interf…
RW Aur B: a modest UX Ori-type companion of the famous primary
Petrov, P.; Takami, M.; Safonov, B. +3 more
The secondary of the famous young binary RW Aur is much less studied than the primary. To rectify this shortcoming, we present here the results of UBVRIJHK photometric, VRI polarimetric and optical spectral observations of RW Aur B. The star demonstrates chaotic brightness variations in the optical band, with irregular, short (∼1-d) dimmings with …
Three Dusty Star-forming Galaxies at z ∼ 1.5: Mergers and Disks on the Main Sequence
Casey, Caitlin M.; Whitaker, Katherine E.; Cooray, Asantha +1 more
The main sequence of galaxies, a correlation between the star formation rates (SFRs) and stellar masses of galaxies, has been observed out to z ∼ 4. Galaxies within the scatter of the correlation are typically interpreted to be secularly evolving while galaxies with SFRs elevated above the main sequence are interpreted to be undergoing interaction…
Dynamic Observing and Tiling Strategies for the DESI Legacy Surveys
Myers, Adam D.; Schlegel, David J.; Weaver, Benjamin A. +22 more
The Dark Energy Spectroscopic Instrument Legacy Surveys, a combination of three ground-based imaging surveys, have mapped 16,000 deg2 in three optical bands (g, r, and z) to a depth 1-2 mag deeper than the Sloan Digital Sky Survey. Our work addresses one of the major challenges of wide-field imaging surveys conducted at ground-based obs…