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TeV Cosmic-Ray Nucleus Acceleration in Shell-type Supernova Remnants with Hard γ-Ray Spectra
Zhang, Shuinai; Liu, Siming; Zeng, Houdun +1 more
The emission mechanism for hard γ-ray spectra from supernova remnants (SNRs) is still a matter of debate. Recent multiwavelength observations of the TeV source HESS J1912+101 show that it is associated with an SNR with an age of ∼100 kyr, making it unlikely produce the TeV γ-ray emission via leptonic processes. We analyzed Fermi observations of it…
Locating the gamma-ray emission region in the brightest Fermi-LAT flat-spectrum radio quasars
Brown, Anthony M.; Acharyya, Atreya; Chadwick, Paula M.
We present a temporal and spectral analysis of the gamma-ray flux from nine of the brightest flat-spectrum radio quasars (FSRQs) detected with the Fermi Large Area Telescope during its first 8 yr of operation, with the aim of constraining the location of the emission region. Using the increased photon statistics obtained from the two brightest fla…
Gauging the effect of supermassive black holes feedback on quasar host galaxies
Kraemer, S. B.; Crenshaw, D. M.; Storchi-Bergmann, T. +6 more
In order to gauge the role that active galactic nuclei play in the evolution of galaxies via the effect of kinetic feedback in nearby QSO 2's (z ~ 0.3), we observed eight such objects with bolometric luminosities $L_{bol} \sim 10^{46}\rm {erg\, s^{-1}}$ using Gemini Multi-Object Spectrograph-integral field units. The emission lines were fitted wit…
GRAVITY K-band spectroscopy of HD 206893 B. Brown dwarf or exoplanet
Lutz, D.; Genzel, R.; Sturm, E. +93 more
Context. Near-infrared interferometry has become a powerful tool for studying the orbital and atmospheric parameters of substellar companions.
Aims: We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital motion.
Method…
Hubble Space Telescope observations of [O III] emission in nearby QSO2s: physical properties of the ionized outflows
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. M. +14 more
We use Hubble Space Telescope/Space Telescope Imaging Spectrograph long-slit G430M and G750M spectra to analyse the extended [O III] λ5007 emission in a sample of 12 nearby (z < 0.12) luminous (Lbol > 1.6 × 1045 erg s-1) QSO2s. The purpose of the study is to determine the properties of the mass outflows of io…
TOI-1231 b: A Temperate, Neptune-sized Planet Transiting the Nearby M3 Dwarf NLTT 24399
Butler, R. Paul; Barclay, Thomas; Triaud, Amaury H. M. J. +59 more
We report the discovery of a transiting, temperate, Neptune-sized exoplanet orbiting the nearby (d = 27.5 pc), M3V star TOI-1231 (NLTT 24399, L 248-27, 2MASS J10265947-5228099). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite and followed up with observations from the Las Cumbres Observatory and the An…
Uncovering erosion effects on magnetic flux rope twist
Pal, Sanchita; Pomoell, Jens; Price, Daniel J. +2 more
Context. Magnetic clouds (MCs) are transient structures containing large-scale magnetic flux ropes from solar eruptions. The twist of magnetic field lines around the rope axis reveals information about flux rope formation processes and geoeffectivity. During propagation MC flux ropes may erode via reconnection with the ambient solar wind. Any eros…
Clumpy Star Formation and AGN Activity in the Dwarf-Dwarf Galaxy Merger Mrk 709
Deller, Adam T.; Stern, Daniel; Reines, Amy E. +2 more
Nearby, low-metallicity dwarf starburst galaxies hosting active galactic nuclei (AGNs) offer the best local analogs to study the early evolution of galaxies and their supermassive black holes (BHs). Here we present a detailed multiwavelength investigation of star formation and BH activity in the low-metallicity dwarf-dwarf galaxy merger Mrk 709. U…
Star Formation Timescales of the Halo Populations from Asteroseismology and Chemical Abundances
Shi, Jianrong; Xiang, Maosheng; Li, Haining +9 more
We combine asteroseismology, optical high-resolution spectroscopy, and kinematic analysis for 26 halo red giant branch stars in the Kepler field in the range of -2.5 < [Fe/H] < -0.6. After applying theoretically motivated corrections to the seismic scaling relations, we obtain an average mass of 0.97 ± 0.03 M⊙ for our sample of ha…
Stellar Population Astrophysics (SPA) with TNG. Atmospheric parameters of members of 16 unstudied open clusters
Vallenari, A.; Bragaglia, A.; Spina, L. +12 more
Context. Thanks to the modern understanding of stellar evolution, we can accurately measure the ages of open clusters (OCs). Given their position, they are ideal tracers of the Galactic disc. Gaia data release 2, besides providing precise parallaxes, led to the detection of many new clusters, opening a new era for the study of the Galactic disc. H…