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Measuring the Obscuring Column of a Disk Megamaser AGN in a Nearby Merger
Comastri, A.; Brusa, M.; Civano, F. +5 more
Active galactic nuclei (AGNs) hosting disk water megamasers are well known to be obscured by large amounts of gas, likely due to the presence along the line of sight of an almost edge-on disky structure orbiting the supermassive black hole. Correcting for the high obscuration is crucial to infer parameters intrinsic to the source, like its luminos…
Small-scale chemical abundance analysis in a blue compact dwarf galaxy SBS 1415+437
Kumari, Nimisha; Aloisi, Alessandra; James, Bethan L. +1 more
We use integral field spectroscopic (IFS) observations from Gemini Multi-Object Spectrograph-North (GMOS-N) to analyse the ionized gas in the principal star-forming region in the blue compact dwarf galaxy SBS 1415+437. The IFS data enable us to map the weak auroral line [O III] λ4363 at a spatial scale of ∼6.5 pc across a region of ∼143 × 143 pc
Microlens mass determination for Gaia's predicted photometric events
Evans, N. W.; Belokurov, V.; Zhang, Z. H. +2 more
We used Gaia Data Release 2 to search for upcoming photometric microlensing events, identifying two candidates with high amplification. In the case of candidate 1, a spectrum of the lens (l1) confirms it is a usdM3 subdwarf with mass ≈0.11M⊙, while the event reaches maximum amplification of 20^{+20}_{-10} mmag on 2019 November 3 (±1d). …
The extended main-sequence turn-off of the Milky Way open cluster Collinder 347
Piatti, Andrés E.; Bonatto, Charles
We made use of the Gaia DR2 archive to comprehensively study the Milky Way open cluster Collinder 347, known until now as a very young object of solar metal content. However, the G versus GBP - GRP colour-magnitude diagram (CMD) of bonafide probable cluster members, selected on the basis of individual stellar proper motions, …
Photometric and Spectral Observations of the W UMa Stars NSVS 4161544 and 1SWASP J034501.24+493659.9. GAIA Challenges
Kjurkchieva, Diana; Popov, Velimir A.; Stateva, Ivanka +1 more
Photometric and spectral observations of the W UMa binaries NSVS 4161544 and 1SWASP J034501.24+493659.9 with periods of around 8 hr are presented. The simultaneous light-curve and radial-velocity-curve solutions revealed that the two targets have over-contact configurations, and their components undergo partial eclipses. The derived parameters of …
Star-formation rates of two GRB host galaxies at z ∼ 2 and a [C II] deficit observed with ALMA
Hashimoto, Tetsuya; Goto, Tomotsugu; Kim, Seong Jin +6 more
The event rate of long gamma-ray bursts (GRBs) is expected to be a useful tracer of cosmic star-formation history. For this purpose, it is necessary to understand what kinds of star formation/galaxies are traced by GRBs. Here we report rest-frame far-infrared (FIR) continuum detections of the GRB 070521 and 080207 host galaxies at z ∼ 2 with Ataca…
Molecular gas content of shell galaxies
Duc, P. -A.; Combes, F.; Mancillas, B.
Shells are fine stellar structures that are identified by their arc-like shapes around a galaxy. They are currently thought to be vestiges of galaxy interactions and/or mergers. The study of their number, geometry, stellar populations, and gas content can help us to derive the interaction or merger history of a galaxy. Numerical simulations have p…
Extension of an Empirical Electron Flux Model From 6 to 20 Earth Radii Using Cluster/RAPID Observations
Taylor, M. G. G. T.; Henderson, M. G.; Rodriguez, J. V. +1 more
An existing empirical model of the electron fluxes at geosynchronous orbit is extended radially outward in the equatorial plane to 6-20 Earth radii (RE) using observations from the Research with Adaptive Particle Imaging Detectors (RAPID) instrument on the Cluster spacecraft. The new model provides electron flux predictions in the energ…
Discovery of a Damped Lyα System in a Low-z Galaxy Group: Possible Evidence for Gas Inflow and Nuclear Star Formation
Heckman, Timothy M.; Tumlinson, Jason; Momjian, Emmanuel +3 more
We present a low-redshift (z = 0.029) damped Lyα (DLA) system in the spectrum of a background quasi-stellar object (QSO). The DLA is associated with an interacting galaxy pair within a galaxy group. We detected weak Lyα emission centered at the absorption trough of the DLA. The emission was likely tracing the neutral H I reservoir around the galax…
XMMU J181227.8-181234: a new ultracompact X-ray binary candidate
in't Zand, J. J. M.; Kuulkers, E.; Keek, L. +3 more
We report the discovery of Type I (thermonuclear) X-ray bursts from the transient source XMMU J181227.8-181234 = XTE J1812-182. We found seven X-ray bursts in Rossi X-ray Timing Explorer observations during the 2008 outburst, confirming the source as a neutron star low-mass X-ray binary. Based on the measured burst fluence and the average recurren…