The GINGARAW database table provides access to the raw GINGA files in FITS format for the LAC experiment. Ginga was the third Japanese X-ray astronomy satellite. It was launched into low Earth orbit on 5th February 1987 and re-entered the atmosphere on 1st November 1991. The scientific payload consisted of the Large Area Counter (LAC; Turner et al. 1989), the All-Sky Monitor (ASM; Tsunemi et al. 1989) and the Gamma-ray Burst Detector (GBD; Murakami et al. 1989). A full description of the satellite is given in Makino et al. (1987). During its lifetime Ginga performed over 1000 pointed observations of approximately 350 different targets, covering all then known classes of cosmic X-ray sources. The LAC experiment, sensitive to X-rays with energy 1.5-37 keV, was the main scientific instrument aboard Ginga. It was designed and built under a Japan-UK collaboration (ISAS, U. Tokyo, Nagoya U., U. Leicester, Rutherford Appleton Lab). It consisted of an array of eight collimated co-aligned proportional counters with a total effective area of approximately 4000 cm<sup>2</sup>. Steel collimators restricted the field of view to 1.1 x 2.0 degrees (FWHM). This database table was last updated by the HEASARC in August 2005. Galactic coordinates were added and some parameters were renamed to adhere to the HEASARC's current parameter naming conventions. This is a service provided by NASA HEASARC .
The GINGALAC database table contains a summary of the contents of the Ginga pointed observations. This table has been produced from the raw Ginga LAC First Reduction Files (FRFs) and contains information of the individual pointings in addition to FITS spectra and light curves, HDS and FITS data cubes and the plots produced during the pipeline processing. These products can be used with either the Ginga data analysis software or the <a href="/docs/xanadu/xanadu.html">XANADU software suite</a>. This archive (database and all the associated products) is a copy of the GINGA LAC data products held at the Leicester Data Archive Service (<a href="http://ledas-www.star.le.ac.uk">http://ledas-www.star.le.ac.uk</a>). It was delivered to the HEASARC in 1999 as part of an archive exchange between the data centers. The original version was updated in October 2008, when the positions (which had been created assuming the wrong equinox) were corrected; in addition, the values of the nh parameter were corrected. This is a service provided by NASA HEASARC .
As tracers of star formation, galaxy assembly and mass distribution, globular clusters have provided important clues to our understanding of early-type galaxies. But their study has been mostly constrained to galaxy groups and clusters where early-type galaxies dominate, leaving the properties of the globular cluster systems (GCSs) of isolated ellipticals as a mostly uncharted territory. We present Gemini-South/GMOS g'i' observations of five isolated elliptical galaxies: NGC 3962, NGC 2865, IC 4889, NGC 2271 and NGC 4240. Photometry of their GCSs reveals clear color bimodality in three of them, remaining inconclusive for the other two. All the studied GCSs are rather poor with a mean specific frequency S_N_~1.5, independently of the parent galaxy luminosity. Considering also previous work, it is clear that bimodality and especially the presence of a significant, even dominant, population of blue clusters occurs at even the most isolated systems, casting doubts on a possible accreted origin of metal-poor clusters as suggested by some models. Additionally, we discuss the possible existence of ultra-compact dwarfs around the isolated elliptical NGC 3962.
We present deep stellar photometry of the Bootes I dwarf spheroidal galaxy in g- and i-band filters, taken with the Dark Energy Camera at Cerro Tololo in Chile. Our analysis reveals a large, extended region of stellar substructure surrounding the dwarf, as well as a distinct overdensity encroaching on its tidal radius. A radial profile of the Bootes I stellar distribution shows a break radius indicating the presence of extra-tidal stars. These observations strongly suggest that Bootes I is experiencing tidal disruption, although not as extreme as that exhibited by the Hercules dwarf spheroidal. Combined with revised velocity dispersion measurements from the literature, we see evidence suggesting the need to review previous theoretical models of the Bootes I dwarf spheroidal galaxy.
We present Gemini South GMOS g, i photometry of 14 intermediate-age Large Magellanic Cloud (LMC) star clusters, namely: NGC 2155, 2161, 2162, 2173, 2203, 2209, 2213, 2231, 2249, Hodge 6, SL 244, 505, 674, and 769, as part of a continuing project to investigate the extended main-sequence turn-off (EMSTO) phenomenon. Extensive artificial star tests were made over the observed field of view. These tests reveal the observed behaviour of photometric errors with magnitude and crowding. The cluster stellar density radial profiles were traced from star counts over the extent of the observed field. We adopt cluster radii and build colour-magnitude diagrams (CMDs) with cluster features clearly identified. We used the cluster (g, g-i) CMDs to estimate ages from the matching of theoretical isochrones. The studied LMC clusters are confirmed to be intermediate-age clusters, which range in age 9.10<log(t)<9.60. NGC 2162 and NGC 2249 look like new EMSTO candidates, in addition to NGC 2209, on the basis of having dual red clumps.
We present wide-field g- and i-band stellar photometry of the Sextans dwarf spheroidal galaxy and its surrounding area out to four times its half-light radius (r_h_=695pc), based on images obtained with the Dark Energy Camera at the 4-m Blanco telescope at CTIO. We find clear evidence of stellar substructure associated with the galaxy, extending to a distance of 82-arcmin (2kpc) from its centre. We perform a statistical analysis of the overdensities and find three distinct features, as well as an extended halo-like structure, to be significant at the 99.7 per cent confidence level or higher. Unlike the extremely elongated and extended substructures surrounding the Hercules dwarf spheroidal galaxy, the overdensities seen around Sextans are distributed evenly about its centre, and do not appear to form noticeable tidal tails. Fitting a King model to the radial distribution of Sextans stars yields a tidal radius r_t_=83.2-arcmin+/-7.1 arcmin (2.08+/-0.18kpc), which implies the majority of detected substructure is gravitationally bound to the galaxy. This finding suggests that Sextans is not undergoing significant tidal disruption from the Milky Way, supporting the scenario in which the orbit of Sextans has a low eccentricity.
The Galactic bulge is a massive, old component of the Milky Way. It is known to host a bar, and it has recently been demonstrated to have a pronounced boxy/peanut structure in its outer region. Several independent studies suggest the presence of more than one stellar populations in the bulge, with different origins and a relative fraction changing across the bulge area. This is the first of a series of papers presenting the results of the Giraffe Inner Bulge Survey, carried out at the ESO-VLT with the multifibre spectrograph FLAMES. Spectra of ~5000 red clump giants in 24 bulge fields have been obtained at resolution R=6500, in the infrared Calcium triplet wavelength region at ~8500{AA}. They are used to derive radial velocities and metallicities, based on new calibration specifically devised for this project. Radial velocities for another ~1200 bulge red clump giants, obtained from similar archive data, have been added to the sample. Higher resolution spectra have been obtained for ~450 additional stars at latitude b=-3.5, with the aim of investigating chemical abundance patterns variations with longitude, across the inner bulge. In total we present here radial velocities for 6494 red clump stars. We present here the target selection criteria, observing strategy and the catalogue with radial velocity measurements for all the target stars.
We investigate metallicity and {alpha}-element abundance gradients along a Galactic longitude strip, at latitude b~-4{deg}, with the aim of providing observational constraints for the structure and origin of the Milky Way bulge. High-resolution (R~22500) spectra for 400 Kgiants, in four fields within -4.8{deg}<~b<~-3.4{deg} and -10{deg}<~l<~+10{deg}, were obtained within the GIRAFFE Inner Bulge Survey (GIBS) project. To this sample we added another ~400 stars in Baade's Window at (l,b)=(1{deg},-4{deg}), observed with the identical instrumental configuration: FLAMES GIRAFFE in Medusa mode with HR13 setup. All target stars lie within the red clump of the bulge colour-magnitude diagram, thus minimising contamination from the disc or halo stars. The spectroscopic stellar surface parameters were derived with an automatic method based on the GALA code, while the [Ca/Fe] and [Mg/Fe] abundances as a function of [Fe/H] were derived through a comparison with the synthetic spectra using MOOG. We constructed the metallicity distributions for the entire sample, and for each field individually, in order to investigate the presence of gradients or field-to-field variations in the shape of the distributions.
We present the first X-ray source catalog of the ASCA Medium Sensitivity Survey (AMSS, or the GIS catalog project), constructed from data at Galactic latitudes |b|>10{deg} observed between 1993 May and 1996 December. The catalog utilizes 368 combined fields and contains 1343 sources with the detection significance above 5{sigma} either in the survey bands of 0.7-7keV, 2-10keV, or 0.7-2keV, including target sources. For each source, the ASCA source name, position, a 90% error radius, count rates in the three bands, detection significances, fluxes, and a hardness ratio are provided. With extensive simulations, we carefully evaluate the data quality of the catalog. Results from cross-correlation with other existing catalogs are briefly summarized.
In succession to the first ASCA Medium Sensitivity Survey catalog (AMSS-I), we present the second X-ray source catalog (AMSS-II), constructed from the Gas Imaging Spectrometer (GIS) data covering Galactic latitudes |b|>10{deg} observed between 1997 January and 2000 May. The AMSS-II catalog uses 306 fields and contains a total of 1190 sources detected with significance of >5{sigma} in either the 0.7-7, 2-10, or 0.7-2keV band. The AMSS-I and AMSS-II catalogs list a total of 2533 sources from an area of 278{deg}^2^ and provides a unique database of X-ray sources in the flux range of 10^-13^-10^-11^ergs/cm^2^/s (0.7-10keV). We summarize statistical properties of a complete X-ray sample consisting of 1969 serendipitous selected from AMSS-I and AMSS-II.