2018A&A...619A.163R


Query : 2018A&A...619A.163R

2018A&A...619A.163R - Astronomy and Astrophysics, volume 619A, 163-163 (2018/11-1)

Unveiling the environment and faint features of the isolated galaxy CIG 96 with deep optical and HI observations.

RAMIREZ-MORETA P., VERDES-MONTENEGRO L., BLASCO-HERRERA J., LEON S., VENHOLA A., YUN M., PERIS V., PELETIER R., VERDOES KLEIJN G., UNDA-SANZANA E., ESPADA D., BOSMA A., ATHANASSOULA E., ARGUDO-FERNANDEZ M., SABATER J., MUNOZ-MATEOS J.C., JONES M.G., HUCHTMEIER W., RUIZ J.E., IGLESIAS-PARAMO J., FERNANDEZ-LORENZO M., BECKMAN J., SANCHEZ-EXPOSITO S. and GARRIDO J.

Abstract (from CDS):


Context. Asymmetries in atomic hydrogen (HI) in galaxies are often caused by the interaction with close companions, making isolated galaxies an ideal framework to study secular evolution. The AMIGA project has demonstrated that isolated galaxies show the lowest level of asymmetry in their HI integrated profiles compared to even field galaxies, yet some present significant asymmetries. CIG 96 (NGC 864) is a representative case reaching a 16% level.
Aims. Our aim is to investigate the HI asymmetries of the spiral galaxy CIG 96 and what processes have triggered the star-forming regions observed in the XUV pseudo-ring.
Methods. We performed deep optical observations at CAHA1.23m, CAHA2.2m and VST (OmegaCAM wide-field camera) telescopes. We reach surface brightness (SB) limits of µCAHA2.2m=27.5mag/arcsec2 (Cousins R) and µVST=28.7mag/arcsec2 (SDSS r) that show the XUV pseudo-ring of the galaxy in detail. Additionally, a wavelet filtering of the HI data cube from our deep observations with VLA/EVLA telescope allowed us to reach a column density of NHI=8.9x1018cm–2 (5σ) (28''x28'' beam), lower than in any isolated galaxy.
Results. We confirm that the HI of CIG 96 extends farther than 4xr25 in all directions. Furthermore, we detect for the first time two gaseous structures (∼106M) in the outskirts. The SDSS g-r colour index image from CAHA1.23m shows extremely blue colours in certain regions of the pseudo-ring where NHI>8.5x1020cm–2, whereas the rest show red colours. Galactic cirrus contaminate the field, setting an unavoidable detection limit at 28.5mag/arcsec2 (SDSS r).
Conclusions. At the current SB and NHI levels, we detect no stellar link within 1°x1° or gaseous link within 40'x40' between CIG 96 and any companion. The isolation criteria rule out interactions with other similar-sized galaxies for at least ∼2.7Gyr. Using existing stellar evolution models, the age of the pseudo-ring is estimated at 1Gyr or older. Undetected previously accreted companions and cold gas accretion remain as the main hypothesis to explain the optical pseudo-ring and HI features of CIG 96.

Abstract Copyright: © ESO 2018

Journal keyword(s): galaxies: individual: NGC 864 - galaxies: spiral - galaxies: structure - galaxies: evolution - galaxies: kinematics and dynamics - radio lines: galaxies

VizieR on-line data: <Available at CDS (J/A+A/619/A163): list.dat fits/*>

Simbad objects: 9

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Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 253 SyG 00 47 33.134 -25 17 19.68   8.03   6.94 8.1 ~ 3039 2
2 UGC 1670 G 02 10 43.492 +06 45 29.60   16.0       ~ 36 0
3 UGC 1677 G 02 11 03.86592 +06 40 01.6140   18       ~ 16 0
4 NGC 864 H2G 02 15 27.641 +06 00 09.43   12.00       ~ 210 1
5 HIPASS J0217+06 HI 02 17 45.8 +06 18 12           ~ 2 0
6 UGC 1803 G 02 20 29.357 +06 48 38.89   15.1       ~ 29 0
7 M 94 SyG 12 50 53.148 +41 07 12.55 9.15 8.96 8.24 7.78   ~ 1265 2
8 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 4110 3
9 NAME Local Group GrG ~ ~           ~ 7314 0

    Equat.    Gal    SGal    Ecl

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2021.07.27-02:22:09

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