Hydrogen Fluoride toward Luminous Nearby Galaxies: NGC 253 and NGC 4945

Abstract

We present the detection of hydrogen fluoride, HF, in two luminous nearby galaxies NGC 253 and NGC 4945 using the Heterodyne Instrument for the Far-Infrared (HIFI) on board the Herschel Space Observatory. The HF line toward NGC 253 has a P-Cygni profile, while an asymmetric absorption profile is seen toward NGC 4945. The P-Cygni profile in NGC 253 suggests an outflow of molecular gas with a mass of M(H${}_2$)${}_{out}$ $\sim$ 1 $\times$ 10${}^7$ M${}_{\odot }$ and an outflow rate as large as M $\sim$ 6.4 M${}_{\odot }$ yr${}^{-1}$. In the case of NGC 4945, the axisymmetric velocity components in the HF line profile is compatible with the interpretation of a fast-rotating nuclear ring surrounding the nucleus and the presence of inflowing gas. The gas falls into the nucleus with an inflow rate of $\le$ 1.2 M${}_{\odot }$ yr${}^{-1}$, inside a inner radius of $\le$ 200 pc. The gas accretion rate to the central AGN is much smaller, suggesting that the inflow can be triggering a nuclear starburst. From these results, the HF $J=1-0$ line is seen to provide an important probe of the kinematics of absorbing material along the sight-line to nearby galaxies with bright dust continuum and a promising new tracer of molecular gas in high-redshift galaxies.

References in corpus (5)

• Massive molecular outflows and negative feedback in ULIRGs observed by Herschel-PACS
• The Starburst-Driven Molecular Wind in NGC 253 and the Suppression of Star Formation
• The Hubble flow around the CenA / M83 galaxy complex
• The Circumnuclear Molecular Gas in the Seyfert Galaxy NGC4945
• SWAS Observations of Water in Molecular Outflows

Cited by in corpus (15)

• A Herschel Space Observatory Spectral Line Survey of Local Luminous Infrared Galaxies from 194 to 671 Microns
• HIFI Spectroscopy of ${\mathrm{H}}_2\mathrm{O}$ submm Lines in Nuclei of Actively Star Forming Galaxies
• Molecular line emission in NGC 4945, imaged with ALMA
• A Herschel/HIFI Legacy Survey of HF and H2O in the Galaxy: Probing Diffuse Molecular Cloud Chemistry
• A thorough view of the nuclear region of NGC 253 - Combined Herschel, SOFIA and APEX dataset
• The ionization rates of galactic nuclei and disks from Herschel/HIFI observations of water and its associated ions
• ExoMol photodissociation cross sections I: HCl and HF
• Detection of 36 GHz Class I Methanol Maser Emission Towards NGC 4945
• The ramp-up of interstellar medium enrichment at z>4
• Collisional quenching of highly rotationally excited HF
• Origin of hydrogen fluoride emission in the Orion Bar: An excellent tracer for CO-dark H2 gas clouds
• Uncovering the nucleus candidate for NGC 253
• Three-dimensional distribution of hydrogen fluoride gas toward NGC6334 I and I(N)
• Etching glass in the early Universe: Luminous HF and water emission in a QSO-SMG pair at z=4.7
• ArH+ and H2O+ absorption towards luminous galaxies