Search Publications
The origin of the X-ray, radio and H I structures in the NGC 5903 galaxy group
Raychaudhury, Somak; Vrtilek, Jan M.; David, Laurence P. +3 more
The NGC 5903 galaxy group is a nearby (∼30 Mpc) system of ∼30 members, dominated by the giant ellipticals NGC 5903 and NGC 5898. The group contains two unusual structures: a ∼110 kpc long H I filament crossing NGC 5903 and a ∼75 kpc wide diffuse, steep-spectrum radio source of unknown origin that overlaps NGC 5903 and appears to be partly enclosed…
Extended VHE γ-ray emission towards SGR1806-20, LBV 1806-20, and stellar cluster Cl* 1806-20
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +242 more
Using the High Energy Spectroscopic System (H.E.S.S.) telescopes we have discovered a steady and extended very high-energy (VHE) γ-ray source towards the luminous blue variable candidate LBV 1806-20, massive stellar cluster Cl* 1806-20, and magnetar SGR 1806-20. The new VHE source, HESS J1808-204, was detected at a statistical significance of >…
HST/GHRS Observations of Cool, Low-gravity Stars. VI. Mass-loss Rates and Wind Parameters for M Giants
Carpenter, Kenneth G.; Nielsen, Krister E.; Rau, Gioia +1 more
The photon-scattering winds of M giants absorb parts of the chromospheric emission lines and produce self-reversed spectral features in high-resolution Hubble Space Telescope (HST)/GHRS spectra. These spectra provide an opportunity to assess fundamental parameters of the wind, including flow and turbulent velocities, the optical depth of the wind …
Spectroscopic Confirmation and Velocity Dispersions for 20 Planck Galaxy Clusters at 0.16 < z < 0.78
Chary, Ranga-Ram; Stern, Daniel; Shim, Hyunjin +8 more
We present Gemini and Keck spectroscopic redshifts and velocity dispersions for 20 clusters detected via the Sunyaev-Zel’dovich (SZ) effect by the Planck space mission, with estimated masses in the range 2.3× {10}14 {M}⊙ < {M}500{Pl}< 9.4× {10}14 {M}⊙ . Cluster members were se…
Geomorphological Evidence for Shallow Ice in the Southern Hemisphere of Mars
McEwen, A. S.; Viola, D.
The localized loss of near-surface excess ice on Mars by sublimation (and perhaps melting) can produce thermokarstic collapse features such as expanded craters and scalloped depressions, which can be indicators of the preservation of shallow ice. We demonstrate this by identifying High Resolution Imaging Science Experiment images containing expand…
LAMOST J221750.59+210437.2: A new member of carbon-enhanced extremely metal-poor stars with excesses of Mg and Si
Honda, Satoshi; Li, Haining; Ishigaki, Miho N. +4 more
We report on the elemental abundances of the carbon-enhanced metal-poor (CEMP) star J2217+2104, discovered through our metal-poor star survey with LAMOST and Subaru. This object is a red giant and has extremely low Fe abundance ([Fe/H] = -4.0) and very large enhancement of C, N, and O with excesses of Na, Mg, Al, and Si. This star is a new example…
Resurrecting the Power-law, Intermediate, and Logamediate Inflations in the DBI Scenario with Constant Sound Speed
Karami, Kayoomars; Rezazadeh, Kazem; Amani, Roonak +1 more
We investigate the power-law, intermediate, and logamediate inflationary models in the framework of DBI non-canonical scalar field with constant sound speed. In the DBI setting, we first represent the power spectrum of both scalar density and tensor gravitational perturbations. Then, we derive different inflationary observables including the scala…
Hubble Space Telescope Observations of 3200 Phaethon at Closest Approach
Mutchler, Max; Jewitt, David; Agarwal, Jessica +1 more
We present Hubble Space Telescope observations of the active asteroid (and Geminid stream parent) 3200 Phaethon when at its closest approach to Earth (separation 0.07 au) in 2017 December. Images were recorded within ∼1° of the orbital plane, providing extra sensitivity to low surface brightness caused by scattering from a large-particle trail. We…
Transiting planet candidate from K2 with the longest period
Bouchy, F.; Eggenberger, P.; Blanco-Cuaresma, S. +8 more
Context. We present the transit and follow-up of a single transit event from Campaign 14 of K2, EPIC248847494b, which has a duration of 54 h and a 0.18% depth.
Aims: Using photometric tools and conducting radial velocity follow-up, we vet and characterise this very strong candidate.
Methods: Owing to the long, unknown period, standard fo…
On the Transition of the Galaxy Quenching Mode at 0.5 < z < 1 in CANDELS
Barro, Guillermo; Pérez-González, Pablo G.; Bell, Eric F. +19 more
We investigate the galaxy quenching process at intermediate redshift using a sample of ∼4400 galaxies with M * > 109 M ⊙ between redshift 0.5 and 1.0 in all five CANDELS fields. We divide this sample, using the integrated specific star formation rate (sSFR), into four subgroups: star-forming galaxies (SFGs) abov…