We present a large sample of over 200 integrated-light spectra of confirmed globular clusters (GCs) associated with the Sombrero (M104) galaxy taken with the Deep Imaging Multi-Object Spectrograph (DEIMOS) instrument on the Keck telescope. A significant fraction of the spectra have signal-to-noise ratio levels high enough to allow measurements of GC metallicities using the method of Brodie & Huchra. We find a distribution of spectroscopic metallicities in the range -2.2<[Fe/H]<+0.1 that is bimodal, with peaks at [Fe/H]~-1.4 and -0.6. Thus, the GC system of the Sombrero galaxy, like a few other galaxies now studied in detail, reveals a bimodal spectroscopic metallicity distribution supporting the long-held belief that colour bimodality reflects two metallicity subpopulations. This further suggests that the transformation from optical colour to metallicity for old stellar populations, such as GCs, is not strongly non-linear. We also explore the radial and magnitude distribution with metallicity for GC subpopulations but small number statistics prevent any clear trends in these distributions.
We present the results of optical (R-band) photometric and polarimetric monitoring and Very Long Baseline Array imaging of the blazar S4 0954+658, along with Fermi {gamma}-ray data during a multi-waveband outburst in 2011 March-April. After a faint state with a brightness level R~17.6mag registered in the first half of 2011 January, the optical brightness of the source started to rise and reached ~14.8mag during the middle of March, showing flare-like behavior. The most spectacular case of intranight variability was observed during the night of 2011 March 9, when the blazar brightened by ~0.7mag within 7hr. During the rise of the flux, the position angle of the optical polarization rotated smoothly over more than 300{deg}. At the same time, within 1{sigma} uncertainty, a new superluminal knot appeared with an apparent speed of 19.0+/-0.3c. We have very strong evidence that this knot is associated with the multi-waveband outburst in 2011 March-April. We also analyze the multi-frequency behavior of S4 0954+658 during a number of minor outbursts from 2008 August to 2012 April. We find some evidence of connections between at least two additional superluminal ejecta and near-simultaneous optical flares.
This paper presents a catalogue of previously unpublished optical and infrared photometry for a sample of 162 emission-line objects and shell stars visible from the southern hemisphere. The data were obtained between 1978 and 1997 in the Walraven (WULBV), Johnson/Cousins UBV(RI)_c_ and ESO and SAAO near-infrared (JHKLM) photometric systems. Most of the observed objects are Herbig Ae/Be (HAeBe) stars or HAeBe candidates appearing in the list of HAeBe candidates of The et al. (1994, Cat. <J/A+AS/104/315>), although several B[e] stars, LBVs and T Tauri are also included in the sample. For many of the stars the data presented here are the first photo-electric measurements in the literature. The resulting catalogue consists of 1809 photometric measurements. Optical variability was detected in 66 out of the 116 sources that were observed more than once. 15 out of the 50 stars observed multiple times in the infrared showed variability at 2.2 microns (K band). Table 1 contains the stars identifiers, positions, types and a summary of the observational data on each star. Tables 2, 3 and 4 contain all obtained photometry in the Walraven WULBV, Johnson/Cousins UBV(RI)_c and ESO and SAAO near-infrared (JHKLM) photometric systems.
Using the ESO/SERC and POSS-I surveys we selected 76 isolated triple systems of galaxies with DE<-3{deg}. For each triplet the equatorial coordinates, type of configuration, angular diameters, apparent angular separation of the components, morphological types, total magnitudes and other characteristics are presented.
Spectra are presented for MK standards in the wavelength range 580-1020nm. The stars cover the normal spectral types O to M and luminosity types I, III, and V. In addition, a small number of peculiar stars are included. The data are in 137 FITS files, in the "fits" subdirectory. The list of the 137 stars is included in the "stars.dat" file; note that the list is not identical to the stars listed in Table1 of the paper.
Stroemgren uvby photometry has been obtained for 270 reddened and very reddened OB stars selected from the Stephenson & Sanduleak (1971) catalogue of Luminous Stars in the Southern Milky Way (LSS), Cat. <III/43>. Corrections have been applied to convert the data as closely as possible to the reddened O stars observed by Crawford (1975PASP...87..481C). Uncorrected and corrected data ar presented in Tables 1 and 3, respectively.
H{beta} photometry is given for 263 reddened and very reddened stars from the Stephenson & Sanduleak (1971, Cat. <III/43>) catalogue of Luminous Stars in the Southern Milky Way (LSS). The results are combined with the uvby photometry presented in Paper I to determine reddenings, E(b-y), and distances for the stars and to estimate the spectral types and luminosity classes from derived T_eff_ and M_V_ values.
V(RI)C photometry has been obtained for 262 reddened and very reddened stars selected from the Stephenson & Sanduleak (1971, Cat. <III/43>) catalogue of Luminous Stars in the Southern Milky Way (LSS). This photometry, together with data from earlier papers in this series, is used to identify a number of probable variable stars.
We present the results of spectroscopic follow-up observations for a sample of 71 red objects with high proper motions in the range 0.08-1.14 arcsec/yr as detected using APM and SuperCOSMOS Sky Surveys (SSS) measurements of multi-epoch photographic Schmidt plates. Red objects were selected by combining the photographic BjRI magnitudes with 2MASS near-infrared JHKs magnitudes. Some 50 of the 71 spectroscopically classified objects turn out to be late-type (>M6) dwarfs and in more detail, the sample includes 35 ultracool dwarfs with spectral types between M8 and L2, some previously reported, as well as five M-type subdwarfs, including a cool esdM6 object, SSSPM J0500-5406. Distance estimates based on the spectral types and 2MASS J magnitudes place almost all of the late-type (>M6) dwarfs within 50pc, with 25 objects located inside the 25pc limit of the catalogue of nearby stars. Most of the early-type M dwarfs are located at larger distances of 100-200pc, suggesting halo kinematics for some of them. All objects with Halpha equivalent widths larger than 10 Angstroms have relatively small tangential velocities (<50km/s). Finally, some late-type but blue objects are candidate binaries.
