TY - JOUR
T1 - Highly perturbed molecular gas in infalling cluster galaxies
T2 - the case of CGCG97-079
AU - Scott, T.C.
AU - Usero, A.
AU - Brinks, E.
AU - Bravo-Alfaro, H.
AU - Cortese, L.
AU - Boselli, A.
AU - Argudo-Fernandez, M.
N1 - Date of Acceptance: 14/07/2015
PY - 2015/10/11
Y1 - 2015/10/11
N2 - We report on CO (J = 2 → 1) mapping with the IRAM 30-m HEtrodyne Receiver Array (HERA) of CGCG 97-079, an irregular galaxy in the merging galaxy cluster Abell 1367 (z = 0.022). We find that ˜80 per cent of the detected CO (J = 2 → 1) is projected within a 16 arcsec2 (6.5 kpc2) region to the north and west of the optical/NIR centre, with the intensity maximum offset ˜10 arcsec (4 kpc) NW of the optical/NIR centre and ˜7 arcsec (3 kpc) south-east of the H I intensity maximum. Evolutionary synthesis models indicate CGCG 97-079 experienced a burst of star formation ˜108 yr ago, most likely triggered by a tidal interaction with CGCG 97-073. For CGCG 97-079 we deduce an infall velocity to the cluster of ˜1000 km s-1 and moderate ram pressure (Pram ≈ 10-11 dyne cm-2). The observed offset in CGCG 97-079 of the highest density H I and CO (J = 2 → 1) from the stellar components has not previously been observed in galaxies currently undergoing ram pressure stripping, although previous detailed studies of gas morphology and kinematics during ram pressure stripping were restricted to significantly more massive galaxies with deeper gravitational potential wells. We conclude the observed cold gas density maxima offsets are most likely the result of ram pressure and/or the high-speed tidal interaction with CGCG 97-073. However ram pressure stripping is likely to be playing a major role in the perturbation of lower density gas.
AB - We report on CO (J = 2 → 1) mapping with the IRAM 30-m HEtrodyne Receiver Array (HERA) of CGCG 97-079, an irregular galaxy in the merging galaxy cluster Abell 1367 (z = 0.022). We find that ˜80 per cent of the detected CO (J = 2 → 1) is projected within a 16 arcsec2 (6.5 kpc2) region to the north and west of the optical/NIR centre, with the intensity maximum offset ˜10 arcsec (4 kpc) NW of the optical/NIR centre and ˜7 arcsec (3 kpc) south-east of the H I intensity maximum. Evolutionary synthesis models indicate CGCG 97-079 experienced a burst of star formation ˜108 yr ago, most likely triggered by a tidal interaction with CGCG 97-073. For CGCG 97-079 we deduce an infall velocity to the cluster of ˜1000 km s-1 and moderate ram pressure (Pram ≈ 10-11 dyne cm-2). The observed offset in CGCG 97-079 of the highest density H I and CO (J = 2 → 1) from the stellar components has not previously been observed in galaxies currently undergoing ram pressure stripping, although previous detailed studies of gas morphology and kinematics during ram pressure stripping were restricted to significantly more massive galaxies with deeper gravitational potential wells. We conclude the observed cold gas density maxima offsets are most likely the result of ram pressure and/or the high-speed tidal interaction with CGCG 97-073. However ram pressure stripping is likely to be playing a major role in the perturbation of lower density gas.
KW - Astrophysics - Astrophysics of Galaxies
U2 - 10.1093/mnras/stv1592
DO - 10.1093/mnras/stv1592
M3 - Article
SN - 0035-8711
VL - 453
SP - 328
EP - 337
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -