Search Publications
Probing the Radio to X-Ray Connection of the Vela X Pulsar Wind Nebula with Fermi LAT and H.E.S.S.
LaMassa, S.; de Jager, O. C.; Slane, P. O.
Morphologically, it appears as if the Vela X pulsar wind nebula (PWN) consists of two emission regions: whereas X-ray (~1 keV) and very high energy (VHE) H.E.S.S. γ-ray observations appear to define a cocoon-type shape south of the pulsar, radio observations reveal an extended area of size 2° × 3° (including the cocoon area), also south of the Vel…
Optical Counterpart of the Ultraluminous X-Ray Source IC 342 X-1
Feng, Hua; Kaaret, Philip
We present Chandra and HST observations of the ultraluminous X-ray source (ULX) IC 342 X-1. The Chandra and HST images are aligned using two X-ray-emitting foreground stars. The astrometry-corrected position for X-1 is R .A . = 03h45m55.61s, decl . = + 68°04'55.3'' (J2000.0), with an error circle of 0.2''. One exte…
Low-Ionization Emission Regions in Quasars: Gas Properties Probed with Broad O I and Ca II Lines
Kawara, K.; Oyabu, S.; Matsuoka, Y.
We have compiled the emission-line fluxes of O I λ8446, O I λ11287, and the near-infrared (IR) Ca II triplet (λ8579) observed in 11 quasars. These lines are considered to emerge from the same gas as do the Fe II lines in the low-ionized portion of the broad emission line region (BELR). The compiled quasars are distributed over wide ranges of redsh…
The Birth Place of the Type Ic Supernova 2007gr
Stephens, Andrew W.; Smartt, Stephen J.; Mattila, Seppo +8 more
We report our attempts to locate the progenitor of the peculiar Type Ic SN 2007gr in Hubble Space Telescope (HST) preexplosion images of the host galaxy, NGC 1058. Aligning adaptive optics Altair/NIRI imaging of SN 2007gr from the Gemini (North) Telescope with the preexplosion HST WFPC2 images, we identify the supernova (SN) position on the HST fr…
Supernovae in Low-Redshift Galaxy Clusters: Observations by the Wise Observatory Optical Transient Search (WOOTS)
Filippenko, Alexei V.; Maoz, Dan; Gal-Yam, Avishay +1 more
We describe the Wise Observatory Optical Transient Search (WOOTS), a survey for supernovae (SNe) and other variable and transient objects in the fields of redshift 0.06-0.2 Abell galaxy clusters. We present the survey design and data analysis procedures, and our object detection and follow-up strategies. We have obtained follow-up spectroscopy for…
Morphologies of Two Massive Old Galaxies at z ~ 2.5
Stockton, Alan; Canalizo, Gabriela; Iye, Masanori +2 more
We present the results of NICMOS imaging of two massive galaxies photometrically selected to have old stellar populations at z ~ 2.5. Both galaxies are dominated by apparent disks of old stars, although one of them also has a small bulge comprising about one-third of the light at rest-frame 4800 Å. The presence of massive disks of old stars at hig…
Cool and Hot Components of a Coronal Bright Point
He, Jiansen; Tian, Hui; Marsch, Eckart +1 more
We performed a systematic study of the Doppler shifts and electron densities measured in an EUV bright point (hereafter BP) observed in more than 10 EUV lines with formation temperatures from log (T/K) = 4.5 to 6.3. Those parts of a BP seen in transition region and coronal lines are defined as its cool and hot components, respectively. We find tha…
Prospects for the Detection of the Deep Solar Meridional Circulation
Birch, A. C.; Braun, D. C.
We perform helioseismic holography to assess the noise in p-mode travel-time shifts which would form the basis of inferences of large-scale flows throughout the solar convection zone. We also derive the expected travel times from a parameterized return (equatorward) flow component of the meridional circulation at the base of the convection zone fr…
HST NICMOS Imaging of z ~ 2, 24 µm-selected Ultraluminous Infrared Galaxies
Helou, George; Colbert, James; Surace, Jason +3 more
We present Hubble Space Telescope NICMOS H-band imaging of 33 ultraluminous infrared galaxies (ULIRGs) at z ~ 2 that were selected from the 24 µm catalog of the Spitzer Extragalactic First Look Survey. The images reveal that at least 17 of the 33 objects are associated with interactions. Up to one-fifth of the sources in our sample could be …
The Globular Cluster Systems around NGC 3311 and NGC 3309
Whitmore, Bradley C.; Rothberg, Barry; Harris, William E. +2 more
We present extensive new photometry in (g', i') of the large globular cluster (GC) system around NGC 3311, the central cD galaxy in the Hydra cluster. Our GMOS data cover a 5.5' field of view and reach a limiting magnitude i' simeq 26.0, about 0.5 mag fainter than the turnover point of the GC luminosity function. We find that NGC 3311 has a huge p…