- ID:
- ivo://CDS.VizieR/J/MNRAS/415/181
- Title:
- Deep spectroscopy of NGC 7009
- Short Name:
- J/MNRAS/415/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present very deep CCD spectrum of the bright, medium-excitation planetary nebula NGC 7009, with a wavelength coverage from 3040 to 11000{AA}. Traditional emission line identification is carried out to identify all the emission features in the spectra, based on the available laboratory atomic transition data. Since the spectra are of medium resolution, we use multi-Gaussian line profile fitting to deblend faint blended lines, most of which are optical recombination lines (ORLs) emitted by singly ionized ions of abundant second-row elements such as C, N, O and Ne.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/119/159
- Title:
- Deep survey of HI-selected galaxies
- Short Name:
- J/ApJS/119/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a 21cm neutral hydrogen survey of approximately 55{deg}^2^ out to a redshift of cz=8340km/s, we have identified 75 extragalactic HI sources. These objects comprise a well-defined sample of extragalactic sources chosen by means that are independent of optical surface brightness selection effects. In this paper we describe the Arecibo survey procedures and HI data, follow-up VLA HI observations made of several unusual sources, and Kitt Peak B-, R-, and I-band photometry for nearly all of the galaxies. We have also gathered information for some of the optically detected galaxies within the same search volume.
- ID:
- ivo://CDS.VizieR/J/ApJ/896/29
- Title:
- Deep UBVRI photometry of NGC6910 members
- Short Name:
- J/ApJ/896/29
- Date:
- 09 Nov 2021 14:21:10
- Publisher:
- CDS
- Description:
- Deep and wide-field optical photometric observations along with multiwavelength archival data sets have been employed to study the physical properties of the cluster NGC 6910. The study also examines the impact of massive stars on their environment. The age, distance, and reddening of the cluster are estimated to be ~4.5Myr, 1.72+/-0.08kpc, and E(B-V)_min_=0.95mag, respectively. The mass function slope ({Gamma}=-0.74+/-0.15) in the cluster region is found to be flatter than the Salpeter value (-1.35), indicating the presence of an excess number of massive stars. The cluster also shows mass segregation toward the central region due to their formation processes. The distribution of warm dust emission is investigated toward the central region of the cluster, showing the signature of the impact of massive stars within the cluster region. Radio continuum clumps powered by massive B-type stars (age range ~0.07-0.12Myr) are traced that are located away from the center of the stellar cluster NGC 6910 (age ~4.5Myr). Based on the values of different pressure components exerted by massive stars, the photoionized gas associated with the cluster is found to be the dominant feedback mechanism in the cluster. Overall, the massive stars in the cluster might have triggered the birth of young, massive B-type stars in the cluster. This argument is supported with evidence of the observed age gradient between the cluster and the powering sources of the radio clumps.
- ID:
- ivo://CDS.VizieR/J/A+A/324/549
- Title:
- Deep UVBRI photometry in IC 348
- Short Name:
- J/A+A/324/549
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table3 contains UBVRI-CCD photometry for the 123 observed stars in the nucleus of IC 348 open cluster. Magnitude and colours are given with their corresponding errors. Column "N" gives the number of observations. Spectral types and cross-identifications with other catalogues are given in note file. Table5 contains adopted reddening solution for the brightest members in IC 348
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/1995
- Title:
- Deep uVI photometry of NGC2419
- Short Name:
- J/MNRAS/431/1995
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present accurate wide-field uVI photometry of the remote and massive Galactic globular cluster NGC 2419, aimed at searching for the u-V colour spread along the red giant branch (RGB) which is generally interpreted as the photometric signature of the presence of multiple populations in globular clusters. Focusing on the RGB stars in the magnitude range 19.8<=V<=22.0, we find that (i) the u-V, u-I and the V-I spreads about the RGB ridge line are significantly larger than that expected from observational errors, accurately quantified by means of extensive artificial stars experiments, (ii) the intrinsic colour spreads in u-V and u-I are larger than in V-I, and (iii) the stars lying to the blue of the RGB ridge line in u-V and u-I are significantly more concentrated towards the cluster centre than those lying to the red of that line. All the above observational facts can be interpreted in a scenario where a sizable fraction of cluster stars belong to a second generation heavily enriched in helium. Finally, we find that bright RGB stars (17.5<V<19.0) having [Mg/Fe]<0.0 lie preferentially on the red side of the cluster RGB, while those having [Mg/Fe]>0.0 lie preferentially on the blue side.
- ID:
- ivo://CDS.VizieR/J/A+A/533/A91
- Title:
- Deep VI imaging in outer regions of M33
- Short Name:
- J/A+A/533/A91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Subaru/Suprime-Cam deep V and I imaging of seven fields in the outer regions of M33. Our aim is to search for stellar structures corresponding to extended HI clouds found in a recent 21-cm survey of the galaxy. Three fields probe a large HI complex to the southeastern (SE) side of the galaxy. An additional three fields cover the northwestern (NW) side of the galaxy along the HI warp. A final target field was chosen further north, at a projected distance of approximately 25kpc, to study part of the large stellar plume recently discovered around M33. We analyse the stellar population at R>10kpc by means of V, I colour magnitude diagrams reaching the red clump. We constrain the age and metallicity of the different stellar populations, search for density enhancements that correspond to the HI features, and investigate the radial surface distribution of the stars. We find evolved stellar populations in all fields out to 120' (~30kpc), while a diffuse population of young stars (~200Myr) is detected out to a galactocentric radius of 15kpc. The mean metallicity in the southern fields remains approximately constant at [M/H]=-0.7 beyond the edge of the optical disc, from 40' out to 80'. Along the northern fields probing the outer HI disc, we also find a metallicity of [M/H]=-0.7 between 35' and 70' from the centre, which decreases to [M/H]=-1.0 at larger angular radii out to 120'. In the northernmost field, outside the disc extent, the stellar population of the large stellar plume possibly related to a M33-M31 interaction is on average more metal-poor ([M/H]=-1.3) and older (>6Gyr). An exponential disc with a large scale-length (~7kpc) fits well the average distribution of stars detected in both the SE and NW regions from a galactocentric distance of 11kpc out to 30kpc. The stellar disc extends beyond the HI disc. The stellar distribution at large radii is disturbed and, although there is no clear correlation between the stellar substructures and the location of the HI clouds, this gives evidence of tidal interaction or accretion events.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A18
- Title:
- Deep VI photometry of 15 dwarf galaxy candidates
- Short Name:
- J/A+A/629/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dwarf galaxy satellite systems are essential probes to test models of structure formation, making it necessary to establish a census of dwarf galaxies outside of our own Local Group. We present deep FORS2 VI band images from the ESO Very Large Telescope (VLT) for 15 dwarf galaxy candidates in the Centaurus group of galaxies. We confirm nine dwarfs to be members of Cen A by measuring their distances using a Bayesian approach to determine the tip of the red giant branch luminosity. We have also fit theoretical isochrones to measure their mean metallicities. The properties of the new dwarfs are similar to those in the Local Group in terms of their sizes, luminosities, and mean metallicities. Within our photometric precision, there is no evidence of a metallicity spread, but we do observe possible extended star formation in several galaxies, as evidenced by a population of asymptotic giant branch stars brighter than the red giant branch tip. The new dwarfs do not show any signs of tidal disruption. Together with the recently reported dwarf galaxies by the complementary PISCeS survey, we study the luminosity function and 3D structure of the group. By comparing the observed luminosity function to the high-resolution cosmological simulation IllustrisTNG, we find agreement within a 90% confidence interval.However, Cen A seems to be missing its brightest satellites and has an overabundance of the faintest dwarfs in comparison to its simulated analogs. In terms of the overall 3D distribution of the observed satellites, we find that the whole structure is flattened along the line-of-sight, with a root-mean-square (rms) height of 130kpc and an rms semi-major axis length of 330kpc. Future distance measurements of the remaining dwarf galaxy candidates are needed to complete the census of dwarf galaxies in the Centaurus group.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A78
- Title:
- Deep VI photometry of Sgr dIrr
- Short Name:
- J/A+A/570/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric catalogue of the dwarf irregular galaxy Sagittarius. The catalogue is obtained from deep V and I band wide field photometry from VIMOS at VLT. Only sources having at least six independent magnitude estimates per filter were included in this catalogue. The average and the standard error of the mean of the independent measures obtained from the different images were adopted as the final values of the instrumental magnitude and of the uncertainty on the relative photometry. The instrumental v and i magnitudes were transformed into the Johnson-Kron-Cousins V,I photometric system using more than 70 bright stars (V<22.5) in common with the publicly available HST Wide Field and Planetary Camera 2 (WFPC2) photometry by Holtzman et al. (2006ApJS..166..534H). The instrumental coordinates were transformed into J2000 Equatorial coordinates with 2nd degree polynomials, using more than 1000 stars in common with the GSC2.2 catalog. Please see Section 2.2 for details.
- ID:
- ivo://CDS.VizieR/J/MNRAS/371/963
- Title:
- Deep VLA survey in Lockman Hole, HDFN, ELAIS N2
- Short Name:
- J/MNRAS/371/963
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present catalogues of faint 1.4-GHz radio sources from extremely deep Very Large Array pointings in the Lockman Hole, the Hubble Deep Field-North (HDF-N) and the European Large Area ISO Survey (ELAIS) N2 field. Our analysis of the HDF-N data has produced maps that are significantly deeper than those previously published, and we have used these to search for counterparts to submillimetre sources. For each of the fields, we have derived normalized differential source counts and in the case of the HDF-N find no evidence for the previously reported underdensity of sources; our counts are entirely consistent with those found for the majority of other fields. The catalogues are available as an online supplement to this paper and the maps are also available for download.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/137
- Title:
- Deep, wide-field g,i imaging of And XXXI
- Short Name:
- J/ApJ/836/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from WIYN pODI imaging of Lacerta I (And XXXI), a satellite dwarf galaxy discovered in the outskirts of the Andromeda galaxy (M31) in Pan-STARRS1 survey data. Our deep, wide-field g,i photometry reaches ~3mag fainter than the photometry in the Pan-STARRS1 discovery paper and allows us to trace the stellar population of Lac I beyond two half-light radii from the galaxy center. We measure a Tip of the Red Giant Branch distance for Lac I of (m-M)_0_=24.44+/-0.11mag (773+/-40kpc, or 264+/-6kpc from M31), which is consistent with the Pan-STARRS1 distance. We use a maximum-likelihood technique to derive structural properties for the galaxy, and find a half-light radius (r_h_) of 3.24+/-0.21' (728+/-47pc), ellipticity ({epsilon}) of 0.44+/-0.03, total magnitude M_V_=-11.4+/-0.3, and central surface brightness {mu}_V,0_=24.8+/-0.3mag/arcsec^2^. We find no H I emission in archival data and set a limit on Lac I's neutral gas mass-to-light ratio of M_HI_/L_V_<0.06M_{sun}_/L_{sun}_, confirming Lac I as a gas-poor dwarf spheroidal galaxy. Photometric metallicities derived from Red Giant Branch stars within 2 r_h_ yield a median [Fe/H] of -1.68+/-0.03, which is more metal-rich than the spectroscopically derived value from Martin+ (2014ApJ...793L..14M). Combining our measured magnitude with this higher metallicity estimate places Lac I closer to its expected position on the luminosity-metallicity relation for dwarf galaxies.