Search Publications
Moving Groups as the Origin of the Vertical Phase Space Spiral in the Solar Neighborhood
Pérez-Villegas, Angeles; Barros, Douglas A.; Michtchenko, Tatiana A. +1 more
Using Gaia data release 2 (DR2), we analyzed the distribution of stars in the close vicinity of the Sun in the full 3D position-velocity space. We have found no evidence of incomplete phase mixing in the vertical direction of the disk, which could have originated from external events. We show that the vertical phase-space spiral Z-V z …
2 mm GISMO Observations of the Galactic Center. I. Dust Emission
Morris, Mark R.; Staguhn, Johannes; Gonzalez-Quiles, Junellie +5 more
The central molecular zone, covering the inner ∼1° of the Galactic plane has been mapped at 2 mm using the Goddard-IRAM Superconducting 2-Millimeter Observer (GISMO) bolometric camera on the 30 m IRAM telescope. The 21″ resolution maps show abundant emission from cold molecular clouds, from star-forming regions, and from one of the Galactic center…
Neutron Stars and Black Holes in the Small Magellanic Cloud: The SMC NuSTAR Legacy Survey
Haberl, F.; Lehmer, B. D.; Hornschemeier, A. E. +18 more
We present a source catalog from the first deep hard X-ray (E > 10 keV) survey of the Small Magellanic Cloud (SMC), the Nuclear Spectroscopic Telescope Array (NuSTAR) Legacy Survey of the SMC. We observed three fields, for a total exposure time of 1 Ms, along the bar of this nearby star-forming galaxy. Fields were chosen for their young stellar…
Evidence of New Magnetic Transitions in Late-type Dwarfs from Gaia DR2
Spada, Federico; Distefano, Elisa; Lanzafame, Alessandro C. +1 more
The second Gaia data release contains the identification of 147,535 low-mass (≲ 1.4 {M}⊙ ) rotational modulation variable candidates on (or close to) the main sequence, together with their rotation period and modulation amplitude. The richness, the period and amplitude range, and the photometric precision of this sample make it possible…
Thermal Emission and Magnetic Beaming in the Radio and X-Ray Mode-switching PSR B0943+10
Mereghetti, Sandro; Turolla, Roberto; Potekhin, Alexander Y. +3 more
PSR B0943+10 is a mode-switching radio pulsar characterized by two emission modes with different radio and X-ray properties. Previous studies, based on simple combinations of blackbody and power-law models, showed that its X-ray flux can be decomposed in a pulsed thermal plus an unpulsed nonthermal components. However, if PSR B0943+10 is a nearly …
XMM-Newton RGS Spectroscopy of the M31 Bulge. I. Evidence for a Past AGN Half a Million Years Ago
Wang, Q. Daniel; Li, Zhiyuan; Foster, Adam R. +3 more
Existing analysis based on spectra from the Reflection Grating Spectrometer (RGS) on board XMM-Newton already shows that the G-ratio of the O VII Heα triplet in the inner bulge of M31 is too high to be consistent with a pure optically thin thermal plasma in collisional ionization equilibrium (CIE). Different processes that may affect properties of…
SOFIA FORCAST Photometry of 12 Extended Green Objects in the Milky Way
Hunter, T. R.; Cyganowski, C. J.; Friesen, R. K. +2 more
Massive young stellar objects (MYSOs) are known to undergo an evolutionary phase in which high mass accretion rates drive strong outflows. A class of objects believed to trace this phase accurately is the Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE) Extended Green Object (EGO) sample, so named for the presence of extended 4.5 …
A Double-modulation Effect Detected in a Double-mode High-amplitude δ Scuti Star: KIC 10284901
Esamdin, Ali; Yang, Tao-Zhi
In this paper, we present an analysis of the pulsating behavior of Kepler target KIC 10284901. The Fourier transform of the high-precision light curve reveals seven independent frequencies for its light variations. Among them, the first two frequencies are main pulsation modes: F0 = 18.994054(1) day-1 and F1 = 24.335804(4) day-1
UV to X-Ray Comptonization Delay in Mrk 493
Dewangan, Gulab C.; Pal, Main; Pawar, Pramod +1 more
The broadband X-ray emission from type 1 active galactic nuclei, dominated by a power-law continuum, is thought to arise from repeated inverse Compton scattering of seed optical/UV photons by energetic electrons in a hot corona. The seed optical/UV photons are assumed to arise from an accretion disk, but direct observational evidence has remained …
First Evidence of Enhanced Recombination in Astrophysical Environments and the Implications for Plasma Diagnostics
Dupree, A. K.; Raymond, J.; García-Rojas, J. +6 more
We report the first unambiguous observational evidence of Rydberg Enhanced Recombination (RER), a potentially important recombination mechanism that has hitherto been unexplored in low-temperature photoionized plasmas. RER shares similarities with dielectronic recombination, with the difference that the electron is captured into a highly excited s…