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Radial variation of whistler-mode chorus: first results from the STAFF/DWP instrument on board the Double Star TC-1 spacecraft
Santolík, O.; Yearby, K. H.; Cornilleau-Wehrlin, N. +2 more
We use the first measurements of the STAFF/DWP instrument on the Double Star TC-1 spacecraft to investigate whistler-mode chorus. We present initial results of a systematic study on radial variation of dawn chorus. The chorus events show an increased intensity at L parameter above 6. This is important for the possible explanation of intensificatio…
Chandra Observations of NGC 4261 (3C 270): Revealing the Jet and Hidden Active Galactic Nucleus in a Type 2 LINER
Zezas, A.; Fabbiano, G.; Birkinshaw, M. +2 more
We present results from a Chandra ACIS-S observation of the type 2 low-ionization nuclear emission-line region (LINER) radio galaxy NGC 4261 (3C 270). The X-ray data show that this galaxy hosts a heavily obscured (NH~8×1022 cm-2) active galactic nucleus (AGN) with an intrinsic luminosity of 2.4×1041 ergs…
Do Young Galaxies Exist in the Local Universe? Red Giant Branch Detection in the Metal-poor Dwarf Galaxy SBS 1415+437
Leitherer, C.; Tosi, M.; van der Marel, R. P. +3 more
We present results from an HST/ACS imaging study of the metal-poor blue compact dwarf galaxy SBS 1415+437. It has been argued previously that this is a very young galaxy that started to form stars only <~100 Myr ago. However, we find that the optical color-magnitude diagram prominently reveals asymptotic giant branch and red giant branch (RGB) …
New Elemental Abundances for V1974 Cygni
Shore, S. N.; Starrfield, S.; Wagner, R. M. +2 more
We present a new analysis of existing optical and ultraviolet spectra of the ONeMg nova V1974 Cygni 1992. Using these data and the photoionization code Cloudy, we have determined the physical parameters and elemental abundances for this nova. Many of the previous studies of this nova have made use of incorrect analyses, and hence a new study was r…
Constraining the Distribution of L and T Dwarfs in the Galaxy
Hathi, N. P.; Ryan, R. E., Jr.; Windhorst, R. A. +1 more
We estimate the thin-disk scale height of the Galactic population of L and T dwarfs based on star counts from 15 deep parallel fields from the Hubble Space Telescope. From these observations, we have identified 28 candidate L and T dwarfs based on their i'-z' color and morphology. By comparing these star counts with a simple Galactic model, we est…
Discovery of two M 32 twins in Abell 1689
Infante, L.; Blakeslee, J. P.; Hilker, M. +5 more
The M 31 satellite galaxy M 32 has long been considered an object of unique properties, being the most extreme example of the very rare compact elliptical galaxy class. Here we present the spectroscopic discovery of two M 32 twins in the massive galaxy cluster Abell 1689. As these objects are so rare, this is an important step towards a better und…
On the X-ray emission of z ∼2 radio galaxies: IC scattering of the CMB and no evidence for fully-formed potential wells
Pentericci, L.; Röttgering, H. J. A.; Miley, G. K. +3 more
We present the results of 20 ks Chandra observations for each of 5 radio galaxies in the redshift range 2.0<z<2.6. The goals were to (i) study the nature of their non-thermal X-ray emission; (ii) investigate the presence and amount of hot gas; and (iii) look for active galactic nuclei (AGN) overdensities in fields around high redshift radio …
The host galaxy/AGN connection in nearby early-type galaxies. Sample selection and hosts brightness profiles
Capetti, A.; Balmaverde, B.
This is the first of a series of three papers exploring the connection between the multiwavelength properties of AGNs in nearby early-type galaxies and the characteristics of their hosts. We selected two samples, both with high resolution 5 GHz VLA observations available and providing measurements down to 1 mJy level, reaching radio-luminosities a…
XTE J1550-564: INTEGRAL Observations of a Failed Outburst
Shrader, C. R.; Sturner, S. J.
The well-known black hole X-ray binary transient XTE J1550-564 underwent an outburst during the spring of 2003, which was substantially underluminous in comparison to previous periods of peak activity in that source. In addition, our analysis shows that it apparently remained in the hard spectral state over the duration of that outburst. This is a…
Diffuse radio emission in a REFLEX cluster
Böhringer, H.; Govoni, F.; Giovannini, G. +2 more
Deep Very Large Array radio observations are presented for the REFLEX clusters RXC J0437.1{+}0043 and RXC J1314.4{-}2515. They are at similar distances and show similar X-ray luminosity, but they are quite different in X-ray structure. Indeed RXC J0437.1{+}0043 is regular and relaxed, whereas RXC J1314.4{-}2515 is characterized by substructure and…