- ID:
- ivo://CDS.VizieR/J/A+A/623/A25
- Title:
- Photometric and astrometric study of NGC 6530
- Short Name:
- J/A+A/623/A25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 6530 is a young cluster, with a complex morphology and star-formation history. We present a statistical study of its global properties, using a new, large list of candidate members down to masses of 0.2-0.4M_{sun}_ and Gaia DR2 astrometry. We consider a larger sky region compared to previous studies, to investigate the entire cluster until its periphery, including any diffuse population all around the main cluster. We study the distribution of extinction and age across the different regions, and obtain constraints on the star-formation history. We also study the dynamics of cluster members. Cluster membership was determined on the basis of literature X-ray data, H{alpha} emission, near-IR and UV excesses from the VPHAS+ and UKIDSS photometric surveys and published near-IR catalogs, and Gaia DR2 astrometry; moreover, we used a method for photometric selection of M-type pre-main-sequence cluster members, which we recently developed and used for other star-formation regions. The list of candidates includes nearly 3700 stars, of which we estimate approximately 2700 to be genuine NGC 6530 members. Using Gaia parallaxes, the cluster distance is found to be 1325pc, with errors of 0.5% (statistical) and 8.5% (systematic), in agreement with previous determinations. The cluster morphology and boundaries are established with great confidence, from the agreement between the subsamples of members selected using different criteria. There is no diffuse population of members around the cluster, but there are minor condensations of true members in addition to the two main groups in the cluster core and in the Hourglass nebula. Two such subgroups are spatially associated with the stars 7 Sgr (F2II-III) and HD 164536 (O7.5V). There is a definite pattern of sequential star formation across the cluster, within an age range from less than 0.5Myr to ~5Myr. Extinction is spatially non-uniform, with part of the population still embedded or obscured by thick dust. The precise Gaia proper motion data indicate that the NGC 6530 parent cloud collided with the Galactic plane around 4Myr ago, and we suggest that event as the trigger of the bulk of star formation in NGC 6530. The internal cluster dynamics is also partially resolved by the Gaia data, indicating expansion of the main cluster population with respect to its center.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/113/483
- Title:
- Photometric and radial velocity of RRLyr stars
- Short Name:
- J/A+AS/113/483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Almost simultaneous measurements in the Geneva seven-colour photometric system and in radial velocities with the spectrometer CORAVEL for five RR Lyrae field stars were obtained in order to apply the Baade-Wesselink method to this kind of variable stars. In this paper the observational data on these stars are presented; the analysis of their physical parameters will be published in the forthcoming paper of the series.
- ID:
- ivo://CDS.VizieR/V/92A
- Title:
- Photometric and Spectroscopic Databases for LSS Stars
- Short Name:
- V/92A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains databases of published photoelectric UBVbeta data, MK-system spectral classifications, and Stroemgren four-color uvby photometry for objects in the Stephenson-Sanduleak "Luminous Stars in the Southern Milky Way" catalog (LSS catalog). The catalog contains mostly OB stars and A and F supergiants. These databases have been compiled from the literature.
- ID:
- ivo://CDS.VizieR/J/AJ/143/129
- Title:
- Photometric and Spectroscopic observations of BF Dra
- Short Name:
- J/AJ/143/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BF Dra is now known to be an eccentric double-lined F6+F6 binary star with relatively deep (0.7mag) partial eclipses. Previous studies of the system are improved with 7494 differential photometric observations from the URSA WebScope and 9700 from the NFO WebScope, 106 high-resolution spectroscopic observations from the Tennessee State University 2m automatic spectroscopic telescope and the 1m coude-feed spectrometer at Kitt Peak National Observatory, and 31 accurate radial velocities from the CfA. Very accurate (better than 0.6%) masses and radii are determined from analysis of the two new light curves and four radial velocity curves. Theoretical models match the absolute properties of the stars at an age of about 2.72Gyr and [Fe/H]=-0.17, and tidal theory correctly confirms that the orbit should still be eccentric. Our observations of BF Dra constrain the convective core overshooting parameter to be larger than about 0.13H_p_. We find, however, that standard tidal theory is unable to match the observed slow rotation rates of the components' surface layers.
- ID:
- ivo://CDS.VizieR/J/A+A/506/999
- Title:
- Photometric Calibration of SNLS
- Short Name:
- J/A+A/506/999
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the photometric calibration of the SuperNova Legacy Survey (SNLS) three year dataset. The SNLS corresponds to the DEEP component of the larger Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The SNLS repeatedly monitors four one square degree fields (labeled D[1-4]) with the MegaCam wide-field imager, in the g, r, i and z bands. u-band observations of the same fields are also available, although not formally part of the SNLS dataset. The non-uniformities of the MegaCam imager photometric response have been mapped as a function of the position on the focal plane. The fluxes, measured on the survey images processed with the CFHT Elixir pipeline, have been corrected for these non-uniformities in order to obtain measurements that are uniform at the ~1% level. The MegaCam passband transmissions were found to be non-uniform, the filters being 3 to 6 nanometers bluer on the edges of the camera than on the center. This result agrees with the filter scans provided by the filter manufacturer (Sagem/REOSC). This has important consequences on the definition of the MegaCam magnitudes: the natural magnitude system depends on the focal plane location where the observations were made. In order not to break the connection between calibrated magnitudes and their physical flux counterparts, we chose to report the *natural magnitudes* of each object, measured in the MegaCam passbands, at the focal plane location where the object was observed. We call this system, "Local Natural Magnitudes". The non-uniformities of the MegaCam effective passbands are small and, for main sequence stellar objects, they may be accounted for using linear color corrections. The relation between the Local Natural Magnitudes of a given star, observed at two locations x_0 and x of the focal plane are: g|x = g|x_0 + dk_g_gr(x) * ( (g-r)|x_0 - (g-r)BD+17|x_0 ) ... z|x = z|x_0 + dk_z_iz(x) * ( (i-z)|x_0 - (i-z)BD+17|x_0 ) where the dk(x) are (position dependant) color terms. We provide dk(x) maps for each MegaCam band (see below). The SNLS 3 year calibration relies on the (Landolt, 1992AJ....104..340) standard star catalog. Landolt fields are observed during each photometric night along with the SNLS fields. Zero-points are derived from these observations. Stable and isolated stars are detected on the SNLS fields and selected as "tertiary standards". The calibrated magnitudes of each tertiary standard obtained under photometric conditions are combined to produce a calibration catalog for each SNLS field. To interpret the tertiary standard magnitudes as physical fluxes, we need a primary standard, i.e. a star with known MegaCam magnitudes and whose spectral energy distribution has been measured absolutely. The SNLS uses BD+17 4708 whose SED has been measured in Bohlin & Gilliland, 2004, Cat. <J/AJ/128/3053> using the HST STIS and NICMOS spectrographs. BD+17 4708 has not been directly observed by SNLS, however, its MegaCam magnitudes were inferred from its known Landolt magnitudes (this paper, table 7). The tertiary star Local Natural Magnitudes are defined so that the associated physical broadband flux f|x is given by: f|x = 10^{-0.4*(m|x-m_ref_)}^*{int}[S_ref(l)_*T(l;x)]dl where m|x is the tertiary star magnitudes at location x on the focal plane, m_ref_ is the MegaCam magnitude of BD+17 4708 (at the center of the focal plane, see table 7 of this paper), S_ref(l)_ is the SED of BD+17 4708 measured in 2004AJ....128.3053B, and T(l;x) is the effective passband of MegaCam at location x. Attached is all the necessary information to tie MegaCam observations to this system. We provide (a) the griz magnitudes of the SNLS tertiary standards for all four SNLS fields (b) the MegaCam open transmission and the ugriz MegaCam filter scans at various position along a diagonal (c) the final uncertainty budget in the form of 3 covariance matrices. The u-band observations of the SNLS DEEP fields are not formally part of the SNLS. Nevetheless we give u-band magnitudes for a subset of the SNLS tertiary stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/3
- Title:
- Photometric catalogs for ECDF-S and CDF-N
- Short Name:
- J/ApJ/742/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of deep multiwavelength data for z~0.3-3 starburst galaxies selected by their 70um emission in the Extended-Chandra Deep Field-South and Extended Groth Strip. We identify active galactic nuclei (AGNs) in these infrared sources through their X-ray emission and quantify the fraction that host an AGN. Lastly, we investigate the ratio between the supermassive black hole accretion rate (inferred from the AGN X-ray luminosity) and the bulge growth rate of the host galaxy (approximated as the SFR) and find that, for sources with detected AGNs and star formation (and neglecting systems with low star formation rates to which our data are insensitive), this ratio in distant starbursts agrees well with that expected from the local scaling relation assuming the black holes and bulges grew at the same epoch. These results imply that black holes and bulges grow together during periods of vigorous star formation and AGN activity.
- ID:
- ivo://CDS.VizieR/J/MNRAS/477/845
- Title:
- Photometric catalogue of CALIFA galaxies
- Short Name:
- J/MNRAS/477/845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extensive compendium of photometrically determined structural properties for all Calar Alto Legacy Integral Field spectroscopy Area (CALIFA)galaxies in the third data release (DR3). We exploit Sloan Digital Sky Survey (SDSS) images in order to extract one-dimensional (1D) gri surface brightness profiles for all CALIFA DR3 galaxies. We also derive a variety of non-parametric quantities and parametric models fitted to 1D i-band profiles. The galaxy images are decomposed using the 2D bulge-disc decomposition programs IMFIT and GALFIT. The relative performance and merit of our 1D and 2D modelling approaches are assessed. Where possible, we compare and augment our photometry with existing measurements from the literature. Close agreement is generally found with the studies of Walcher et al. (2014A&A...569A...1W) and Mendez-Abreu et al. (2017A&A...598A..32M, Cat. J/A+A/598/A32), though some significant differences exist. Various structural metrics are also highlighted on account of their tight dispersion against an independent variable, such as the circular velocity.
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/80
- Title:
- Photometric Classification Catalogue of SDSS DR7
- Short Name:
- J/MNRAS/419/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of about six million unresolved photometric detections in the Sloan Digital Sky Survey (SDSS) Seventh Data Release, classifying them into stars, galaxies and quasars. We use a machine learning classifier trained on a subset of spectroscopically confirmed objects from 14th to 22nd magnitude in the SDSS i band. Our catalogue consists of 2430625 quasars, 3544036 stars and 63586 unresolved galaxies from 14th to 24th magnitude in the SDSS i-band. Our algorithm recovers 99.96 per cent of spectroscopically confirmed quasars and 99.51 per cent of stars to i~21.3 in the colour window that we study. The level of contamination due to data artefacts for objects beyond i=21.3 is highly uncertain and all mention of completeness and contamination in the paper are valid only for objects brighter than this magnitude. However, a comparison of the predicted number of quasars with the theoretical number counts shows reasonable agreement.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A44
- Title:
- Photometric classification of QSO from RCS-2
- Short Name:
- J/A+A/584/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new quasar candidate catalogs from the Red-Sequence Cluster Survey 2 (RCS-2), identified solely from photometric information using a Random Forest algorithm. The algorithm is trained using a well-defined SDSS spectroscopic sample of quasars and stars. The algorithm identifies putative quasars from broadband magnitudes (g, r, i, z) and colors. Exploiting NUV GALEX measurements for a subset of the objects, we refine the classifier by adding new information. An additional subset of the data with WISE W1 and W2 bands is also studied. Upon analyzing 542,897 RCS-2 point sources, the algorithm identified 21,501 quasar candidates, with a training-set-derived precision of 89.5% and recall of 88.4%. These performance metrics improve for the GALEX subset; 6530 quasar candidates are identified from 16898 sources, with a precision and recall respectively of 97.0% and 97.5%. Algorithm performance is further improved when WISE data are included, with precision and recall increasing to 99.3% and 99.1% respectively for 21834 quasar candidates from 242902 sources. After merging these samples and removing duplicates, we obtain 38257 candidates.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/3649
- Title:
- Photometric data for ASASSN-15ed
- Short Name:
- J/MNRAS/453/3649
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the spectroscopic and photometric monitoring campaign of ASASSN-15ed. The transient was discovered quite young by the All Sky Automated Survey for SuperNovae (ASAS-SN) survey. Amateur astronomers allowed us to sample the photometric SN evolution around maximum light, which we estimate to have occurred on JD=2457087.4+/-0.6 in the r band. Its apparent r-band magnitude at maximum was r=16.91+/-0.10, providing an absolute magnitude M_r_~-20.04+/-0.20, which is slightly more luminous than the typical magnitudes estimated for Type Ibn SNe. The post-peak evolution was well monitored, and the decline rate (being in most bands around 0.1 mag/d during the first 25 d after maximum) is marginally slower than the average decline rates of SNe Ibn during the same time interval. The object was initially classified as a Type Ibn SN because early-time spectra were characterized by a blue continuum with superimposed narrow P-Cygni lines of HeI, suggesting the presence of a slowly moving (1200-1500 km/s), He-rich circumstellar medium. Later on, broad P-Cygni HeI lines became prominent. The inferred velocities, as measured from the minimum of the broad absorption components, were between 6000 and 7000 km/s. As we attribute these broad features to the SN ejecta, this is the first time we have observed the transition of a Type Ibn SN to a Type Ib SN.
