- ID:
- ivo://CDS.VizieR/J/A+A/622/A4
- Title:
- LOFAR observations XMM-LSS field
- Short Name:
- J/A+A/622/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of the XMM Large-Scale Structure (XMM-LSS) field observed with the LOw Frequency ARray (LOFAR) at 120-168MHz. Centred at a J2000 declination of -4.5{deg}, this is a challenging field to observe with LOFAR because of its low elevation with respect to the array. The low elevation of this field reduces the effective collecting area of the telescope, thereby reducing sensitivity. This low elevation also causes the primary beam to be elongated in the north-south direction, which can introduce side lobes in the synthesised beam in this direction. However the XMM-LSS field is a key field to study because of the wealth of ancillary information, encompassing most of the electromagnetic spectrum. The field was observed for a total of 12 hours from three four-hour LOFAR tracks using the Dutch array. The final image presented encompasses ~27deg^2^, which is the region of the observations with a >50% primary beam response. Once combined, the observations reach a central rms of 280uJy/beam at 144MHz and have an angular resolution of 7.5x8.5". We present our catalogue of detected sources and investigate how our observations compare to previous radio observations. This includes investigating the flux scale calibration of these observations compared to previous measurements, the implied spectral indices of the sources, the observed source counts and corrections to obtain the true source counts, and finally the clustering of the observed radio sources.
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- ID:
- ivo://CDS.VizieR/J/A+A/648/A2
- Title:
- LOFAR Two-metre Sky Survey Deep Fields DR1
- Short Name:
- J/A+A/648/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The LOFAR Two-metre Sky Survey (LoTSS) will cover the full northern sky and, additionally, aims to observe the LoTSS deep fields to a noise level of <~10uJy/beam over several tens of square degrees in areas that have the most extensive ancillary data. This paper presents the ELAIS-N1 deep field, the deepest of the LoTSS deep fields to date. With an effective observing time of 163.7 hours, it reaches a root mean square (RMS) noise level of <~20uJy/beam in the central region (and below 30uJy/beam over 10 square degrees). The resolution is 6 arcsecs and 84862 radio sources were detected in the full area (68 square degrees) with 74127 sources in the highest quality area at less than 3 degrees from the pointing centre. The observation reaches a sky density of more than 5000 sources per square degree in the central region (5 square degrees).We present the calibration procedure, which addresses the special configuration of some observations and the extended bandwidth covered (115 to 177MHz; central frequency 146.2MHz) compared to standard LoTSS. We also describe the methods used to calibrate the flux density scale using cross-matching with sources detected by other radio surveys in the literature. We find the flux density uncertainty related to the flux density scale to be 6.5 per cent. By studying the variations of the flux density measurements between different epochs, we show that relative flux density calibration is reliable out to about a 3 degree radius, but that additional flux density uncertainty is present for all sources at about the 3 per cent level; this is likely to be associated with residual calibration errors, and is shown to be more significant in datasets with poorer ionosphere conditions. We also provide intra-band spectral indices, which can be useful to detect sources with unusual spectral properties. The final uncertainty in the flux densities is estimated to be 10 per cent for ELAIS-N1.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A3
- Title:
- LOFAR Two-metre Sky Survey Deep Fields DR1
- Short Name:
- J/A+A/648/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the source associations, cross-identifications, and multi-wavelength properties of the faint radio source population detected in the deep tier of the LOFAR Two Metre Sky Survey (LoTSS): the LoTSS Deep Fields. The first LoTSS Deep Fields data release consists of deep radio imaging at 150MHz of the ELAIS-N1, Lockman Hole, and Bootes fields, down to RMS sensitives of around 20, 22, and 32uJy/beam, respectively. These fields are some of the best studied extra-galactic fields in the northern sky, with existing deep, wide-area panchromatic photometry from X-ray to infrared wavelengths, covering a total of ~26 square degrees. We first generated improved multi-wavelength catalogues in ELAIS-N1 and Lockman Hole; combined with the existing catalogue for Bootes, we present forced, matched aperture photometry for over 7.2 million sources across the three fields. We identified multi-wavelength counterparts to the radio detected sources, using a combination of the Likelihood Ratio method and visual classification, which greatly enhances the scientific potential of radio surveys and allows for the characterisation of the photometric redshifts and the physical properties of the host galaxies. The final radio-optical cross-matched catalogue consists of 81951 radio-detected sources, with counterparts identified and multi-wavelength properties presented for 79820 (>97%) sources. We also examine the properties of the host galaxies, and through stacking analysis find that the radio population with no identified counterpart is likely dominated by AGN at z~3-4. This dataset contains one of the largest samples of radio-selected star-forming galaxies and active galactic nuclei (AGN) at these depths, making it ideal for studying the history of star-formation, and the evolution of galaxies and AGN across cosmic time.
- ID:
- ivo://CDS.VizieR/J/ApJ/754/67
- Title:
- Longslit spectroscopy of local bulges
- Short Name:
- J/ApJ/754/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Marcario Low Resolution Spectrograph (LRS) at the Hobby-Eberly- Telescope (HET) to study the kinematics of pseudobulges and classical bulges in the nearby universe. We present major-axis rotational velocities, velocity dispersions, and h3 and h4 moments derived from high-resolution (39km/s) spectra for 45 S0 to Sc galaxies; for 27 of the galaxies we also present minor axis data. We combine our kinematics with bulge-to-disk decompositions. We demonstrate for the first time that purely kinematic diagnostics of the bulge dichotomy agree systematically with those based on Sersic index. Low Sersic index bulges have both increased rotational support (higher v/sigma values) and on average lower central velocity dispersions. Further- more, we confirm that the same correlation also holds when visual morphologies are used to diagnose bulge type. The previously noted trend of photometrically flattened bulges to have shallower velocity dispersion profiles turns to be significant and systematic if the Sersic index is used to distinguish between pseudobulges and classical bulges. The anti-correlation between h3 and v/sigma observed in elliptical galaxies is also observed in intermediate type galaxies, irrespective of bulge type. Finally, we present evidence for formerly undetected counter rotation in the two systems NGC 3945 and NGC 4736.
- ID:
- ivo://CDS.VizieR/J/MNRAS/451/2723
- Title:
- Low-redshift clusters in the SAMI Pilot Survey
- Short Name:
- J/MNRAS/451/2723
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using new integral field observations of 106 galaxies in three nearby clusters, we investigate how the intrinsic scatter of the Fundamental Plane depends on the way in which the velocity dispersion and effective radius are measured. Our spatially resolved spectroscopy, combined with a cluster sample with negligible relative distance errors, allows us to derive a Fundamental Plane with minimal systematic uncertainties. From the apertures we tested, we find that velocity dispersions measured within a circular aperture with radius equal to one effective radius minimizes the intrinsic scatter of the Fundamental Plane. Using simple yet powerful Jeans dynamical models, we determine dynamical masses for our galaxies. Replacing luminosity in the Fundamental Plane with dynamical mass, we demonstrate that the resulting Mass Plane has further reduced scatter, consistent with zero intrinsic scatter. Using these dynamical models, we also find evidence for a possibly non-linear relationship between dynamical mass-to-light ratio and velocity dispersion.
446. LRG catalog
- ID:
- ivo://CDS.VizieR/J/MNRAS/380/1608
- Title:
- LRG catalog
- Short Name:
- J/MNRAS/380/1608
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work I discuss the necessary steps for deriving photometric redshifts for luminous red galaxies (LRGs) and galaxy clusters through simple empirical methods. The data used are from the Sloan Digital Sky Survey (SDSS). I show that with three bands only (gri) it is possible to achieve results as accurate as the ones obtained by other techniques, generally based on more filters. In particular, the use of the (g-i) colour helps improving the final redshifts (especially for clusters), as this colour monotonically increases up to z~0.8. For the LRGs I generate a catalogue of ~1.5 million objects at z<0.70. The accuracy of this catalogue is sigma=0.027 for z<=0.55 and sigma=0.049 for 0.55<z<=0.70. The photometric redshift technique employed for clusters is independent of a cluster selection algorithm. Thus, it can be applied to systems selected by any method or wavelength, as long as the proper optical photometry is available. When comparing the redshift listed in literature to the photometric estimate, the accuracy achieved for clusters is sigma=0.024 for z<=0.30 and sigma=0.037 for 0.30<z<=0.55. However, when considering the spectroscopic redshift as the mean value of SDSS galaxies on each cluster region, the accuracy is at the same level as found by other authors: sigma=0.011 for z<=0.30 and sigma=0.016 for 0.30<z<=0.55. The photometric redshift relation derived here is applied to thousands of cluster candidates selected elsewhere. I have also used galaxy photometric redshifts available in SDSS to identify groups in redshift space and then compare the redshift peak of the nearest group to each cluster redshift. This procedure provides an alternative approach for cluster selection, especially at high redshifts, as the cluster red sequence may be poorly defined.
- ID:
- ivo://CDS.VizieR/J/A+A/405/99
- Title:
- LSB galaxies in near-infrared. I.
- Short Name:
- J/A+A/405/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of about 3800 Low Surface Brightness (LSB) galaxies was selected using the all-sky near-infrared (J, H and Ks-band) 2MASS survey. The selected objects have a mean central surface brightness within a 5" radius around their centre fainter than 18mag/arcsec^2^ in the Ks band, making them the lowest surface brightness galaxies detected by 2MASS. A description is given of the relevant properties of the 2MASS survey and the LSB galaxy selection procedure, as well as of basic photometric properties of the selected objects. The latter properties are compared to those of other samples of galaxies, of both LSBs and "classical'' high surface brightness (HSB) objects, which were selected in the optical. The 2MASS LSBs have a B_Tc_-K_T_ colour colour which is on average 0.9mag bluer than that of HSBs from the NGC. The 2MASS sample does not appear to contain a significant population of red objects.
- ID:
- ivo://CDS.VizieR/J/A+A/408/67
- Title:
- LSB galaxies in near-infrared. II.
- Short Name:
- J/A+A/408/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 367 Low Surface Brightness galaxies detected in the 2MASS all-sky near-infrared survey have been observed in the 21 cm H I line using the Arecibo telescope. All have a Ks-band mean central surface brightness, measured within a 5" radius, fainter than 18mag/arcsec^2^. We present global H I line parameters for the 107 clearly detected objects and the 21 marginal detections, as well as upper limits for the undetected objects. The 107 clear detections comprise 15 previously uncatalogued objects and 36 with a PGC entry only.
- ID:
- ivo://CDS.VizieR/J/A+A/408/465
- Title:
- LSB galaxies in near-infrared. III.
- Short Name:
- J/A+A/408/465
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 334 Low Surface Brightness galaxies detected in the 2MASS all-sky near-infrared survey have been observed in the 21 cm H I line using the Nancay telescope. All have a Ks-band mean central surface brightness, measured within a 5" radius, fainter than 18mag/arcsec^2^ and a Ks-band isophotal radius at the 20mag/arcsec^2^ level larger than 20". We present global H I line parameters for the 171 clearly detected objects and the 23 marginal detections, as well as upper limits for the undetected objects. The 171 clear detections comprise 50 previously uncatalogued objects and 41 objects with a PGC entry only.
450. LSBG catalogue
- ID:
- ivo://CDS.VizieR/J/MNRAS/304/297
- Title:
- LSBG catalogue
- Short Name:
- J/MNRAS/304/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed an automatic technique to search for low-surface-brightness (LSB) galaxies in the local Universe (v<=5000km/s) using the automated plate measuring (APM) scan data of UK Schmidt photographic plates. We optimized our technique and selection criteria by surveying the known LSB galaxies in the Fornax cluster. Plate-to-plate magnitude calibrations were carried out using independent CCD sequences. The galaxies we detected are brighter than 20Bmag, have scalesizes greater than 3arcsec and a central surface brightness fainter than 22.5mag/arcsec^2^. In total 2435 LSB galaxies were detected over a total area of 2187deg^2^. The survey covers the Fornax cluster, NGC 1400, Sculptor and Dorado groups and the field between. We detect on average 32 LSB galaxies per 5.8{deg}x5.8{deg} field. We have estimated the background (v>5000km/s) contamination in three ways: by numerical modelling, using a limited redshift sample and comparing our Fornax data with those of Ferguson. The results indicate a contamination of about 19 galaxies per field.
