Search Publications
A Chandra-HETG View of MCG +8-11-11
Nowak, M. A.; Murphy, K. D.
We present a spectral analysis of the 118 ks Chandra High Energy Transmission Gratings (HETG) observation of the X-ray bright Seyfert 1.5 galaxy MCG +8-11-11, in conjunction with 100 ks of archival Suzaku data, aimed at investigating the signatures of warm absorption and Compton reflection reported from previous Suzaku and XMM-Newton studies of th…
Stellar Encounter Driven Red-giant Star Mass Loss in Globular Clusters
Chung, Chul; Pasquato, Mario; Lee, Young-Wook +5 more
Globular cluster (GC) color-magnitude diagrams (CMDs) are reasonably well understood in terms of standard stellar evolution. However, there are still some open issues, such as fully accounting for the horizontal branch (HB) morphology in terms of chemical and dynamical parameters. Mass loss on the red giant branch (RGB) shapes the mass distributio…
The Temperature of Quiescent Streamers during Solar Cycles 23 and 24
Landi, E.; Testa, P.
Recent in-situ determinations of the temporal evolution of the charge state distribution in the fast and slow solar wind have shown a general decrease in the degree of ionization of all the elements in the solar wind along solar cycles 23 and 24. Such a decrease has been interpreted as a cooling of the solar corona which occurred during the declin…
Blue Straggler Star Populations in Globular Clusters. I. Dynamical Properties of Blue Straggler Stars in NGC 3201, NGC 6218, and ω Centauri
Puzia, Thomas H.; Simunovic, Mirko
We present the first dynamical study of blue straggler stars (BSSs) in three Galactic globular clusters, NGC 3201, NGC 5139 (ω Cen), and NGC 6218, based on medium-resolution spectroscopy (R ≈ 10, 000) obtained with the Inamori-Magellan Areal Camera & Spectrograph mounted at the 6.5 m Baade Magellan telescope. Our BSS candidate selection techni…
Herschel Observations of Dust around the High-mass X-Ray Binary GX 301-2
Chaty, S.; Rahoui, F.; Servillat, M. +2 more
We aim at characterizing the structure of the gas and dust around the high-mass X-ray binary GX 301-2, a highly obscured X-ray binary hosting a hypergiant (HG) star and a neutron star, in order to better constrain its evolution. We used Herschel PACS to observe GX 301-2 in the far infrared and completed the spectral energy distribution of the sour…
The Shock-induced Star Formation Sequence Resulting from a Constant Spiral Pattern Speed
Martínez-García, Eric E.; Puerari, Ivânio
We utilize a suite of multiwavelength data of nine nearby spirals to analyze the shock-induced star formation sequence that may result from a constant spiral pattern speed. The sequence involves tracers as the H I, CO 24 µm, and FUV, where the spiral arms were analyzed with Fourier techniques in order to obtain their azimuthal phases as a fu…
The CoRoT Discovery of a Unique Triple-mode Cepheid in the Galaxy
Poretti, E.; Baglin, A.; Weiss, W. W.
The exploitation of the CoRoT treasure of stars observed in the exoplanetary field allowed the detection of a unusual triple-mode Cepheid in the Milky Way, CoRoT 0223989566. The two modes with the largest amplitudes and a period ratio of 0.80 are identified with the first (P 1 = 1.29 days) and second (P 2 = 1.03 days) radial …
The Jet and Arc Molecular Clouds toward Westerlund 2, RCW 49, and HESS J1023-575 12CO and 13CO (J = 2-1 and J = 1-0) observations with NANTEN2 and Mopra Telescope
Aharonian, F.; Fukui, Y.; Onishi, T. +20 more
We have made new CO observations of two molecular clouds, which we call "jet" and "arc" clouds, toward the stellar cluster Westerlund 2 and the TeV γ-ray source HESS J1023-575. The jet cloud shows a linear structure from the position of Westerlund 2 on the east. In addition, we have found a new counter jet cloud on the west. The arc cloud shows a …
The RR Lyrae Variable Population in the Phoenix Dwarf Galaxy
Sarajedini, Ata; Yang, Soung-Chul; Ordoñez, Antonio J.
We present the first detailed study of the RR Lyrae variable population in the Local Group dSph/dIrr transition galaxy, Phoenix, using previously obtained HST/WFPC2 observations of the galaxy. We utilize template light curve fitting routines to obtain best fit light curves for RR Lyrae variables in Phoenix. Our technique has identified 78 highly p…
GHOSTS I: A New Faint Very Isolated Dwarf Galaxy at D = 12 ± 2 Mpc
Bell, Eric F.; Holwerda, Benne W.; Monachesi, Antonela +8 more
We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) fields. Its detected individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color-magnitude diagrams (CMDs) to compare wit…