2024-03-28T16:02:25Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/26422022-10-10T10:56:45Zcom_10261_135com_10261_4col_10261_388
A new water vapor megamaser
Cernicharo, José
Pardo Carrión, Juan Ramón
Weiss, Axel
Galaxies: individual (Arp 220)
Galaxies: ISM
Galaxies: starburst
ISM: abundances
Radio lines: ISM
We report on the detection of a new megamaser, the 3_1,3–2_2,0 H2O line (v0 = 183.310 GHz) in Arp 220, using the Institut de Radioastronomie Millimétrique (IRAM) 30 m telescope. The line is about 350 km s^-1 wide with a total luminosity of ∼2.5x10^8 K km s^-1 pc2. Although OH megamasers were first discovered in this source, no emission is seen in the 6_1,6–5_2,3 H2O transition (v0=22.235 GHz), a line otherwise detected as a megamaser in about 50 sources to date. This fact puts interesting constraints on the physical conditions of the central region of Arp 220 that are further strengthened by the HCN and HNC J=3–2 and J=1–0 luminosities [in the range (1.5–10)x10^8 K km s^-1 pc^2]. A scenario with ∼106 star-forming cores similar to those found in Sgr B2 in the
central kiloparsec of Arp 220 would be compatible with these data and would explain the lack of 22 GHz H2O emission. This result opens up the possibility of using the 183 GHz H2O line as an additional tool to explore the physical conditions in luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs, respectively) and their starburst or active galactic nucleus (AGN) nature, with a potential interest for high angular resolution
observations with the Atacama Large Millimeter Array (ALMA).
2007-12-28T15:34:21Z
2007-12-28T15:34:21Z
2006-07-20
artículo
The Astrophysical Journal 646: L49–L52, (2006)
1538-4357
http://hdl.handle.net/10261/2642
10.1086/506473
eng
openAccess
American Astronomical Society
University of Chicago Press