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J/A+A/608/A142  Fornax Deep Survey with VST. III. LSB galaxies  (Venhola+, 2017)

The Fornax Deep Survey with VST. III. Low surface brightness dwarfs and ultra diffuse galaxies in the center of the Fornax cluster. Venhola A., Peletier R., Laurikainen E., Salo H., Lisker T., Iodice E., Capaccioli M., Kleijn G.V., Valentijn E., Mieske S., Hilker M., Wittmann C., van de Ven G., Grado A., Spavone M., Cantiello M., Napolitano N., Paolillo M., Falcon-Barroso J. <Astron. Astrophys., 608, A142 (2017)> =2017A&A...608A.142V (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Morphology Keywords: galaxies: dwarf - galaxies: photometry - galaxies: evolution - galaxies: clusters: individual: Fornax Abstract: Studies of low surface brightness (LSB) galaxies in nearby clusters have revealed a sub-population of extremely diffuse galaxies with central surface brightness of µ0,g'>24mag/arcsec2, total luminosity Mg' fainter than -16mag and effective radius between 1.5kpc<Re<10kpc. The origin of these ultra diffuse galaxies (UDGs) is still unclear, although several theories have been suggested. As the UDGs overlap with the dwarf-sized galaxies in their luminosities, it is important to compare their properties in the same environment. If a continuum is found between the properties of UDGs and the rest of the LSB population, it would be consistent with the idea that they have a common origin. Our aim is to exploit the deep g', r' and i'-band images of the Fornax Deep Survey (FDS), in order to identify LSB galaxies in an area of 4deg2 in the center of the Fornax cluster. The identified galaxies are divided into UDGs and dwarf-sized LSB galaxies, and their properties are compared. We identified visually all extended structures having r'-band central surface brightness of µ0,r'>23mag/arcsec2. We classified the objects based on their appearance into galaxies and tidal structures, and perform 2D Sersic model fitting with GALFIT to measure the properties of those classified as galaxies. We analyzed their radial distribution and orientations with respect of the cluster center, and with respect to the other galaxies in our sample. We also studied their colors and compare the LSB galaxies in Fornax with those in other environments. Our final sample complete in the parameter space of the previously known UDGs, consists of 205 galaxies of which 196 are LSB dwarfs (with Re<1.5kpc) and nine are UDGs (Re>1.5kpc). We show that the UDGs have (1) g'-r' colors similar to those of LSB dwarfs of the same luminosity; (2) the largest UDGs (Re>3kpc) in our sample appear different from the other LSB galaxies, in that they are significantly more elongated and extended; whereas (3) the smaller UDGs differ from the LSB dwarfs only by having slightly larger effective radii; (4) we do not find clear differences between the structural parameters of the UDGs in our sample and those of UDGs in other galaxy environments; (5) we find that the dwarf LSB galaxies in our sample are less concentrated in the cluster center than the galaxies with higher surface brightness, and that their number density drops within 180 kpc from the cluster center. We also compare the LSB dwarfs in Fornax with the LSB dwarfs in the Centaurus group, where data of similar quality to ours is available. (6) We find the smallest LSB dwarfs to have similar colors, sizes and Sersic profiles regardless of their environment. However, in the Centaurus group the colors become bluer with increasing galaxy magnitudes, an effect which is probably due to smaller mass and hence weaker environmental influence of the Centaurus group. Our findings are consistent with the small UDGs forming the tail of a continuous distribution of less extended LSB galaxies. However, the elongated and distorted shapes of the large UDGs could imply that they are tidally disturbed galaxies. Due to limitations of the automatic detection methods and uncertainty in the classification the objects, it is yet unclear what is the total contribution of the tidally disrupted galaxies in the UDG population. Description: We use the ongoing Fornax Deep Survey (FDS), which consists of the combined data of the Guaranteed Time Observation Surveys FOCUS (P.I. R. Peletier) and VEGAS (P.I. E. Iodice), dedicated to the Fornax cluster. Both surveys are performed with the ESO VLT Survey Telescope (VST), which is a 2.6-m diameter optical telescope located at Cerro Paranal, Chile. The imaging is done with the OmegaCAM instrument, using the u', g', r' and i'-bands, and 1°x1° field of view. The observations used in this work were gathered in visitor mode runs during November 2013, 2014 and 2015 (ESO P92, P94 and P96, respectively). All the observations were performed in clear (photometric variations <10%) or photometric conditions. The observations in u' and g'-bands were obtained in dark time, and those of the other bands in gray or dark time. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tabled1.dat 99 205 Parameters of the LSB galaxies in our sample
Byte-by-byte Description of file: tabled1.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Name of the object (FDCNN_LSBNN) 12 A1 --- n_Name [*] Note on Name (1) 14- 19 F6.3 deg RAdeg Right ascension (J2000) 21- 27 F7.3 deg DEdeg Declination (J2000) 29- 32 F4.2 --- b/a Axial ratio 34- 37 F4.2 --- e_b/a rms uncertainty on b/a 39- 44 F6.2 deg theta Position angle (east of north) 46- 50 F5.2 mag r'mag Sloan r' magnitude 52- 55 F4.2 mag e_r'mag rms uncertainty on r'mag (2) 57- 61 F5.1 arcsec Re Effective radius in r'-band 63- 66 F4.1 arcsec e_Re rms uncertainty on Re (2) 68- 71 F4.2 --- n Sersic index 73- 76 F4.2 --- e_n rms uncertainty on n (2) 78- 81 F4.2 mag g'-r' Sloan g'-r' colour index 83- 86 F4.2 mag e_g'-r' rms uncertainty on g'-r' (2) 88- 93 A6 --- FCC Possible FCC number (Cat. VII/180) 95- 99 A5 --- Ref Identifications in earlier works (3)
Note (1): * indicates that it was fit using a additional PSF component for the nucleus. Note (2): The error estimations for each parameter are adopted from the tests made with the mock galaxies in Sect. 5.4.2. Note (3): References as follows: a = Ferguson (1989AJ.....98..367F, Cat. VII/180) b = Bothun et al. (1991ApJ...376..404B) c = Munoz et al. (2015, Cat. J/ApJ/813/L15) d = Mieske et al. (2007, Cat. J/A+A/463/503)
History: From electronic version of the journal References: Iodice et al., Paper I 2016ApJ...820...42I Iodice et al., Paper II 2017ApJ...839...21I
(End) Patricia Vannier [CDS] 20-Feb-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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