Dense gas in nearby galaxies XIV .
نویسندگان
چکیده
version lines of ammonia (NH 3) have been detected toward the nuclear 40 ′′ sized bar of the nearby spiral galaxy Maffei 2. The relative intensities of the ammonia lines are characterized by a rotational temperature of 85 K. This is higher than rotational temperatures measured toward IC 342 and most Galactic Center clouds, implying kinetic temperatures > ∼ 100 K. Since the kinetic temperature of the gas is larger than that of the dust, NH 3 is tracing a particularly dense warm gas component that is heated by young massive stars, cloud-cloud collisions, or ion-slip heating in the nuclear starburst. The gas north of the nucleus (V LSR = –80 km s −1) is more highly excited than the gas further south (+6 km s −1). This asymmetry might be related to pronounced morphological distortions that are observed in the northeastern part of the galaxy.
منابع مشابه
Dense gas in nearby galaxies XIV . Detection of hot ammonia in Maffei 2
The (J, K) = (1,1), (2,2), (3,3), and (4,4) inversion lines of ammonia (NH3) have been detected toward the nuclear 40′′ sized bar of the nearby spiral galaxy Maffei 2. The relative intensities of the ammonia lines are characterized by a rotational temperature of 85 K. This is higher than rotational temperatures measured toward IC 342 and most Galactic Center clouds, implying kinetic temperature...
متن کاملA&a Manuscript No. Astronomy and Astrophysics Dense Gas in Nearby Galaxies Xiv. Detection of Hot Ammonia in Maaei 2
version lines of ammonia (NH 3) have been detected toward the nuclear 40 00 sized bar of the nearby spiral galaxy Maaei 2. The relative intensities of the ammonia lines are characterized by a rotational temperature of 85 K. This is higher than rotational temperatures measured toward IC 342 and most Galactic Center clouds, implying kinetic temperatures > 100 K. Since the kinetic temperature of t...
متن کاملObservations of Dense Molecular Gas in a Quasar Host Galaxy at Z=6.42: Further Evidence for a Non-linear Dense Gas – Star Formation Relation at Early Cosmic Times
We report a sensitive search for the HCN(J=2→1) emission line towards SDSS J114816.64+525150.3 (hereafter: J1148+5251) at z=6.42 with the Very Large Array (VLA). HCN emission is a star formation indicator, tracing dense molecular hydrogen gas (n(H2) ≥ 10 4 cm) within star-forming molecular clouds. No emission was detected in the deep interferometer maps of J1148+5251. We derive a limit for the ...
متن کاملDense Gas Tracers and Star Formation Laws in Active Galaxies: Apex Survey of Hcn J=4→3 Hco J=4→3, and Cs J=7→6
We report CS J=7→6, HCN J=4→3, and HCO J=4→3 observations in 20 nearby star-forming galaxies with the Acatama Pathfinder EXperiment 12-m telescope. Combined with 4 CS, 4 HCN, and 3 HCO detections in literature, we probe the empirical link between the luminosity of molecular gas (L′gas) and that of infrared emission (LIR), up to the highest gas densities (106 108cm−3 ) that have been probed so f...
متن کاملThe Star Formation Relation in Nearby Galaxies
I review observational studies of the large-scale star formation process in nearby galaxies. A wealth of new multi-wavelength data provide an unprecedented view on the interplay of the interstellar medium and (young) stellar populations on a few hundred parsec scale in 100+ galaxies of all types. These observations enable us to relate detailed studies of star formation in the Milky Way to the z...
متن کامل