The first ground-based detection of the 752 GHz water line in local ultraluminous infrared galaxies using APEX-SEPIA
Journal article, 2024
We report the first ground-based detection of the water line p-H2O (211-202) at 752.033 GHz in three z < 0.08 ultraluminous infrared galaxies (ULIRGs): IRAS 06035-7102, IRAS 17207-0014, and IRAS 09022-3615. Using the Atacama Pathfinder EXperiment (APEX), with its Swedish-ESO PI Instrument for APEX (SEPIA) band-9 receiver, we detect this H2O line with overall signal-to-noise ratios of 8-10 in all three galaxies. Notably, this is the first detection of this line in IRAS 06035-7102. Our new APEX-measured fluxes, between 145 and 705 Jy km s-1, are compared with previous values taken from Herschel SPIRE FTS. We highlight the great capabilities of APEX for resolving the H2O line profiles with high spectral resolutions while also improving by a factor of two the significance of the detection within moderate integration times. While exploring the correlation between the p-H2O(211-202) and the total infrared luminosity, our galaxies are found to follow the trend at the bright end of the local ULIRG's distribution. The p-H2O(211-202) line spectra are compared to the mid-J CO and HCN spectra, and dust continuum previously observed with ALMA. In the complex interacting system IRAS 09022-3615, the profile of the water emission line is offset in velocity with respect to the ALMA CO(J = 4-3) emission. For IRAS 17207-0014 and IRAS 06035-7102, the profiles between the water line and the CO lines are spectroscopically aligned. This pilot study demonstrates the feasibility of directly conducting ground-based high-frequency observations of this key water line, opening the possibility of detailed follow-up campaigns to tackle its nature.
infrared: galaxies
galaxies: ISM
ISM: molecules
Author
Daysi Quinatoa
University of Valparaíso
Chentao Yang
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
E. Ibar
University of Valparaíso
Elizabeth Humphreys
European Southern Observatory Santiago
Atacama Large Millimeter-submillimeter Array (ALMA)
Susanne Aalto
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Loreto Barcos-Munoz
University of Virginia
National Radio Astronomy Observatory
E. Gonzalez-Alfonso
University of Alcalá
C. M. V. Impellizzeri
Leiden University
Y. Jaffé
University of Valparaíso
Universidad Técnica Federico Santa María
Lijie Liu
Cosmic Dawn Center (DAWN)
Technical University of Denmark (DTU)
S. Martin
European Southern Observatory Santiago
Atacama Large Millimeter-submillimeter Array (ALMA)
Axel Weiss
Max Planck Society
Zhi-Yu Zhang
Nanjing University
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 527 3 6321-6331Exploring the Hidden Dusty Nuclei of Galaxies (HIDDeN)
European Research Council (ERC) (789410), 2018-10-01 -- 2023-09-30.
Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.1093/mnras/stad3441