Search Publications
A Detailed X-Ray Investigation of PSR J2021+4026 and the γ-Cygni Supernova Remnant
Cheng, K. S.; Takata, J.; Wang, Y. +9 more
We have investigated the field around the radio-quiet γ-ray pulsar, PSR J2021+4026, with a ~140 ks XMM-Newton observation and ~56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature, which suggests that the pulsation originated from a hot polar cap with T ~ 3 × 106
X-Ray Emission from the Taffy (VV254) Galaxies and Bridge
Boulanger, F.; Helou, G.; Appleton, P. N. +11 more
We present the first X-ray observations of the Taffy galaxies (UGC 12914/5) with the Chandra observatory and detect soft X-ray emission in the region of the gas-rich, radio-continuum-emitting Taffy bridge. The results are compared to Herschel observations of dust and diffuse [C ii] line-emitting gas. The diffuse component of the Taffy bridge has a…
Herschel Observations of the W3 GMC (II): Clues to the Formation of Clusters of High-mass Stars
Martin, P. G.; Hill, T.; White, G. J. +18 more
The W3 giant molecular cloud is a prime target for investigating the formation of high-mass stars and clusters. This second study of W3 within the HOBYS Key Program provides a comparative analysis of subfields within W3 to further constrain the processes leading to the observed structures and stellar population. Probability density functions (PDFs…
HST Images Flash Ionization of Old Ejecta by the 2011 Eruption of Recurrent Nova T Pyxidis
Williams, Robert E.; Bond, Howard E.; Schaefer, Bradley E. +8 more
T Pyxidis is the only recurrent nova known to be surrounded by knots of material ejected in previous outbursts. Following the eruption that began on 2011 April 14.29, we obtained seven epochs (from 4 to 383 days after eruption) of Hubble Space Telescope narrowband Hα images of T Pyx. The ionizing flash of radiation from the nova event had no disce…
Near-Earth Cosmic Ray Decreases Associated with Remote Coronal Mass Ejections
Owens, M. J.; Lockwood, M.; Thomas, S. R. +2 more
Galactic cosmic ray (GCR) flux is modulated by both particle drift patterns and solar wind structures on a range of timescales. Over solar cycles, GCR flux varies as a function of the total open solar magnetic flux and the latitudinal extent of the heliospheric current sheet. Over hours, drops of a few percent in near-Earth GCR flux (Forbush decre…
Detection of a Light Echo from the Otherwise Normal SN 2007af
Garnavich, P. M.; Riess, A. G.; Milne, P. A. +5 more
We present the discovery of a light echo from SN 2007af, a normal Type Ia supernova (SN Ia) in NGC 5584. Hubble Space Telescope images taken three years post explosion reveal two separate echoes: an outer echo and an extended central region, which we propose to be an inner echo for which details are unresolved. Multiple images were obtained in the…
Chandra and Xmm-Newton Observations of the Bimodal Planck SZ-Detected Cluster Plckg345.40-39.34 (A3716) with High and Low Entropy Subcluster Cores
Andrade-Santos, Felipe; Dawson, William A.; Jones, Christine +11 more
We present results from Chandra, XMM-Newton, and ROSAT observations of the Planck SZ-detected cluster A3716 (PLCKG345.40-39.34-G345). We show that G345 is, in fact, two subclusters separated on the sky by 400 kpc. We measure the subclusters’ gas temperatures (∼2-3 keV), total (∼1-2 × 1014 {{M}⊙ }) and gas (∼1-2 × 1013
Mapping High-velocity Hα and Lyα Emission from Supernova 1987A
Smith, Nathan; Garnavich, Peter; France, Kevin +12 more
We present new Hubble Space Telescope images of high-velocity Hα and Lyα emission in the outer debris of SN 1987 A. The Hα images are dominated by emission from hydrogen atoms crossing the reverse shock (RS). For the first time we observe emission from the RS surface well above and below the equatorial ring (ER), suggesting a bipolar or conical st…
Multiplicity among F-type stars. II.
Chini, R.; Fuhrmann, K.
In continuation of our previous study we present an updated census of new companions and model atmosphere analyses for some 50 southern dwarfs, mostly in the mass range 0.90≤slant M≤slant 1.10 {M}⊙ . For the common-proper-motion companions µ Vir B, HR 2225 B, HD 67199 B, and HD 114853 B, we confirm their physical association from …
Deep Multi-telescope Photometry of NGC 5466. II. The Radial Behavior of the Mass Function Slope
Dalessandro, E.; Bellazzini, M.; Beccari, G. +3 more
We use a combination of data acquired with the Advanced Camera for Survey on board the Hubble Space Telescope and the Large Binocular Camera (LBC-blue) mounted on the Large Binocular Telescope to sample the main sequence (MS) stars of the globular cluster (GC) NGC 5466 in the mass range 0.3 < M/M⊙ < 0.8. We derive the cluster's Lu…