Search Publications
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…
The M dwarf problem: Fe and Ti abundances in a volume-limited sample of M dwarf stars
Wallerstein, George; Woolf, Vincent M.
We report iron and titanium abundance measurements from high-resolution spectra in a volume-limited sample of 106 M0 and M0.5 dwarf stars. The sample includes stars north of the celestial equator and closer than 29 parsecs. The results imply that there is an M dwarf problem similar to the previously known G dwarf problem, in that the fraction of l…
Deviations from the Infrared-radio Correlation in Massive, Ultracompact Starburst Galaxies
Moustakas, John; Coil, Alison L.; Rudnick, Gregory H. +11 more
Feedback through energetic outflows has emerged as a key physical process responsible for transforming star-forming galaxies into the quiescent systems observed in the local universe. To explore this process, this paper focuses on a sample of massive and compact merger remnant galaxies hosting high-velocity gaseous outflows ( $| v| \gtrsim {10}^{3…
A multiwavelength search for black widow and redback counterparts of candidate γ-ray millisecond pulsars
Tiengo, A.; Belfiore, A.; Marelli, M. +6 more
The wealth of detections of millisecond pulsars (MSPs) in γ-rays by Fermi has spurred searches for these objects among the several unidentified γ-ray sources. Interesting targets are a sub-class of binary MSPs, dubbed 'black widows' (BWs) and 'redbacks' (RBs), which are in orbit with low-mass non-degenerate companions fully or partially ablated by…
Speckle Interferometry of Nearby Multiple Stars: 2007-2019 Positional Measurements and Orbits of Eight Objects
Dyachenko, V.; Beskakotov, A.; Maksimov, A. +4 more
The orbits of eight systems with low-mass components (HIP 14524, HIP 16025, HIP 28671, HIP 46199, HIP 47791, HIP 60444, HIP 61100, and HIP 73085) are presented. Speckle interferometric data were obtained at the 6 m Big Telescope Alt-azimuth Special Astrophysical Observatory of the Russian Academy of Sciences (BTA SAO RAS) from 2007 to 2019. New da…