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The nuclear environment of the NLS1 Mrk 335: Obscuration of the X-ray line emission by a variable outflow
Harrison, F. A.; Schartel, N.; Santos-Lleó, M. +12 more
We present XMM-Newton, NuSTAR, Swift, and Hubble Space Telescope observations of the Narrow-line Seyfert 1 galaxy Mrk 335 in a protracted low state in 2018 and 2019. The X-ray flux is at the lowest level so far observed, and the extremely low continuum flux reveals a host of soft X-ray emission lines from photoionized gas. The simultaneous UV flux…
The structure of the Mg II broad line emitting region in Type 1 AGNs
Popović, Luka Č.; Kovačević-Dojčinović, Jelena; Marčeta-Mandić, Sladjana
We investigate the structure of the Mg II broad line emission region in a sample of 284 Type 1 active galactic nuclei (AGNs), through comparing the kinematical parameters of the broad Mg II and broad Hβ lines. We found that the Mg II emitting region has more complex kinematics than the Hβ one. It seems that the Mg II broad line originates from two…
UVIT Open Cluster Study. II. Detection of Extremely Low Mass White Dwarfs and Post-Mass Transfer Binaries in M67
Jadhav, Vikrant V.; Subramaniam, Annapurni; Sindhu, N.
A detailed study of the UV-bright stars in the old open star cluster M67 is presented based on the far-UV observations using the Ultra Violet Imaging Telescope (UVIT) on ASTROSAT. The UV and UV-optical color-magnitude diagrams (CMDs), along with overlaid isochrones, are presented for the member stars, which include blue straggler stars (BSSs), tri…
Benchmark ages for the Gaia benchmark stars
Feltzing, Sofia; Lindegren, Lennart; Sahlholdt, Christian L. +1 more
In the era of large-scale surveys of stars in the Milky Way, stellar ages are crucial for studying the evolution of the Galaxy. But determining ages of field stars is notoriously difficult; therefore, we attempt to determine benchmark ages for the extensively studied Gaia benchmark stars which can be used for validation purposes. By searching the …
Chemical Abundances along the 1G Sequence of the Chromosome Maps: The Globular Cluster NGC 3201
Milone, A. P.; Cordoni, G.; Marino, A. F. +10 more
The Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs) has investigated multiple stellar populations by means of the “chromosome map” (ChM) diagnostic tool that maximizes the separation between stars with different chemical compositions. One of the most challenging features revealed by ChM analysis is the apparent in…
Neutral Gas Properties and Lyα Escape in Extreme Green Pea Galaxies
Jaskot, Anne E.; Yun, Min S.; Dowd, Tara +3 more
Mechanisms regulating the escape of Lyα photons and ionizing radiation remain poorly understood. To study these processes, we analyze Very Large Array 21 cm observations of one Green Pea (GP), J160810+352809 (hereafter J1608), and Hubble Space Telescope Cosmic Origins Spectrograph (COS) spectra of 17 GP galaxies at z< 0.2. All are highly ionize…
A statistically significant lack of debris discs in medium separation binary systems
Wyatt, Mark C.; Kennedy, Grant M.; Su, Kate Y. L. +1 more
We compile a sample of 341 binary and multiple star systems with the aim of searching for and characterizing Kuiper belt-like debris discs. The sample is assembled by combining several smaller samples studied in previously published work with targets from two unpublished Herschel surveys. We find that 38 systems show excess emission at 70 or 100 &…
Detections of [O III] 88 µm in two quasars in the reionization epoch
Inoue, Akio K.; Hashimoto, Takuya; Tamura, Yoichi +3 more
We report on detections with the Atacama Large Millimeter/sub-millimeter Array of the far-infrared [O III] 88 µm line and the underlying dust continuum in two quasars in the reionization epoch, J205406.48-000514.8 (hereafter J2054-0005) at z = 6.0391 ± 0.0002 and J231038.88+185519.7 (hereafter J2310+1855) at z = 6.0035 ± 0.0007. The [O III] …
Tensile Strength of Porous Dust Aggregates
Kataoka, Akimasa; Tatsuuma, Misako; Tanaka, Hidekazu
Comets are thought to have information about the formation process of our solar system. Recently, detailed information about comet 67P/Churyumov-Gerasimenko was found by Rosetta. It is remarkable that its tensile strength was estimated. In this paper, we measure and formulate the tensile strength of porous dust aggregates using numerical simulatio…
Random Forest identification of the thin disc, thick disc, and halo Gaia-DR2 white dwarf population
Solano, E.; Rebassa-Mansergas, A.; Torres, S. +3 more
Gaia-DR2 has provided an unprecedented number of white dwarf candidates of our Galaxy. In particular, it is estimated that Gaia-DR2 has observed nearly 400 000 of these objects and close to 18 000 up to 100 pc from the Sun. This large quantity of data requires a thorough analysis in order to uncover their main Galactic population properties, in pa…