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NuStar Hard X-Ray View of Low-luminosity Active Galactic Nuclei: High-energy Cutoff and Truncated Thin Disk
Ho, Luis C.; Younes, George; Yuan, Feng +5 more
We report the analysis of simultaneous XMM-Newton+Nuclear Spectroscopic Telescope Array (NuSTAR) observations of two low-luminosity active galactic nuclei (LLAGNs), NGC 3998 and NGC 4579. We do not detect any significant variability in either source over the ∼3 day length of the NuSTAR observations. The broadband 0.5-60 keV spectrum of NGC 3998 is…
The Period-Luminosity Relations of Red Supergiants in M33 and M31
Yang, Ming; Jiang, Bi-Wei; Gao, Jian +1 more
Based on previously selected preliminary samples of red supergiants (RSGs) in M33 and M31, the foreground stars and luminous asymptotic giant branch stars are further excluded, which leads to the samples of 717 RSGs in M33 and 420 RSGs in M31. With the time-series data from the Intermediate Palomar Transient Factory survey spanning nearly 2000 day…
Interpretation of Departure from the Broad-line Region Scaling in Active Galactic Nuclei
Czerny, Bożena; Panda, Swayamtrupta; Du, Pu +7 more
Most results of the reverberation monitoring of active galaxies showed a universal scaling of the time delay of the Hβ emission region with the monochromatic flux at 5100 Å, with very small dispersion. Such a scaling favored the dust-based formation mechanism of the broad-line region (BLR). Recent reverberation measurements showed that actually a …
Stellar binaries that survive supernovae
Kochanek, C. S.; Belczynski, K.; Auchettl, K.
The number of binaries containing black holes (BH) or neutron stars (NS) depends critically on the fraction of binaries that survive supernova (SN) explosions. We searched for surviving star plus remnant binaries in a sample of 49 supernova remnants (SNR) containing 23 previously identified compact remnants and three high-mass X-ray binaries (HMXB…
The H I velocity function: a test of cosmology or baryon physics?
Obreschkow, Danail; Lagos, Claudia del P.; Elahi, Pascal J. +3 more
Accurately predicting the shape of the H I velocity function (VF) of galaxies is regarded widely as a fundamental test of any viable dark matter model. Straightforward analyses of cosmological N-body simulations imply that the Λ cold dark matter (ΛCDM) model predicts an overabundance of low circular velocity galaxies when compared to observed H I …
A Panchromatic View of the Bulge Globular Cluster NGC 6569
Dalessandro, E.; Salaris, M.; Saracino, S. +12 more
We used high-resolution optical Hubble Space Telescope/WFC3 and multiconjugate adaptive optics assisted GEMINI GeMS/Gemini South Adaptive Optics Imager observations in the near-infrared (NIR) to investigate the physical properties of the globular cluster (GC) NGC 6569 in the Galactic bulge. We have obtained the deepest purely NIR color-magnitude d…
Galaxy-Galaxy lensing in HSC: Validation tests and the impact of heterogeneous spectroscopic training sets
Sifón, Cristóbal; Leauthaud, Alexie; Eisenstein, Daniel J. +9 more
Although photometric redshifts (photo-z's) are crucial ingredients for current and upcoming large-scale surveys, the high-quality spectroscopic redshifts currently available to train, validate, and test them are substantially non-representative in both magnitude and colour. We investigate the nature and structure of this bias by tracking how objec…
Atomic Transition Probabilities for UV and Blue Lines of Fe II and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
Sneden, C.; Lawler, J. E.; Den Hartog, E. A. +2 more
We report new branching fractions (BFs) for 121 UV lines from the low-lying odd-parity levels of Fe II belonging to the z6Do, z6Fo, z6Po, z4Fo, z4Do, and z4Po terms of the 3d6(5D)4p configuration…
Ruprecht 147: A Paradigm of Dissolving Star Cluster
Carraro, Giovanni; Seleznev, Anton F.; Montalto, Marco +1 more
We employed recent Gaia/DR2 data to investigate the dynamical status of the nearby (300 pc), old (2.5 Gyr) open cluster Ruprecht 147. We found prominent leading and trailing tails of stars along the cluster orbit, which demonstrates that Ruprecht 147 is losing stars at fast pace. Star counts indicate the cluster has a core radius of 33.3 arcmin an…
Tracing Kinematic and Chemical Properties of Sagittarius Stream by K-Giants, M-Giants, and BHB stars
Tian, Hao; Zhao, Gang; Wu, Yaqian +12 more
We characterize the kinematic and chemical properties of ∼3000 Sagittarius (Sgr) stream stars, including K-giants, M-giants, and blue horizontal branch stars (BHBs), selected from SEGUE-2, Large Sky Area Multi-Object Fibre Spectroscopic Telescope, and Sloan Digital Sky Survey separately in Integrals-of-Motion space. The orbit of the Sgr stream is …