Extragalac c HF Molecular Line Observa ons from Herschel SPIRE and HIFI Spectroscopy Steve Lord, Raquel Monje, Nanyao Lu, Yinghe Zhao, Darek Lis, Tom Phillips, David Neufeld, Edith Falgarone The HF (J=1-0) transi on at 1.23 THz (243 um) is providing a new diagnos c probe of the molecular gas abundance, excita on, and column density toward infrared bright galaxy nuclei. During the Herschel mission, this transi on was detected and resolved in four galaxies with HIFI and gave 12 upper limits (below right). SPIRE gave strong detec ons of HF emission in 15 sources and absorp on in 11 sources. (Data were taken from the Key program of Lu et al, the OT program of Lord et al., and the Herschel Archive). HIFI (resolved) 4 detec ons, 12 upper limits Mrk 231 SPIRE Detec on (Van NGC 253 detec on in 3 LO se ng with HIFI showed such der Werf) (broad red hump) The 2nd column shows the H and V polariza on excellent signal to noise that it could be deconvolved from the resolved by HIFI! (central peak). separately. They should agree to confirm a double sideband. Here HF absorp on and emission is (unresolved) detec on. SPIRE 26 detec ons Likewise, M82 absorp on feature compared with H2CO absorp on. (blue absorp on feature).
The para- H2O 220-211 at 1.229 THz is typically seen alongside HF transi on at 1.232 THz
IRAS 13120-5453 NGC 6701 IRAS 05442+1732 MRK 231 NGC 253
MGC-03-04-014 NGC 5135 M 231 NGC 1068 CO J=1-0 for comparison shown below. The HF detec on is centered on Vsys.
NGC 4945 M82
NGC 7130 NGC 3256 NGC 7552 NGC 7469 Emission
IRASF 17207-0014 NGC 2623 Mrk 273 IRASF 16399-0937 NGC 1365 Maffei 2 Absorp on
NGC 2146 SE IRAS 17578-0400 CGCG 049-057 UGC 05101
IC 342 NGC 1068
NGC 6240 NGC 0317B MGC+08-11-002 NGC 6286a
Arp 220 UGC 08739 Arp 299 NGC 23 Discussion NGC 2146 It has been recognized (Neufeld et al. 2005, 2010) via fundamental energe c considera ons that HF is the dominant NGC 3256 reservoir of fluorine in the ISM. Preliminary Herschel studies iden fied the transi on in Milky Way objects while subsequent Herschel observa ons have allowed us to extend our view to IR-bright galaxy nuclei and even to their spiral arms (e.g. NGC 2146 SE). Here we show numerous examples the J=1-0 HF transi on occurring both absorp on and emission toward IR-bright galac c nuclei. While SPIRE has yielded the strong detec ons shown above, there is li le assurance that, within the profiles shown, we are not seeing the superposi on of regions of emission and absorp on, thus making interpreta on difficult. E.g.: In NGC 253 the combina on of the two effects yields a p-Cygni profile, which Monje et al. (2013) interpret as tracing two velocity components: in-fall and ou low toward the nucleus. From this example we see the need for high spectral resolu on observa ons of the line. Below, we show evidence that the emission regions are consistent with regions of warm dust which may fill the beam, conceivably the result of AGN-hea ng (see talk here of M. Pereira Santaella) while the absorp on lines may originate in a narrow line-of-sight to a background nuclear con nuum IC 694 NGC 3690 source. (See figure below). Is this line, in emission, a new AGN diagnos c? Clearly high-z ALMA studies are needed here! Counter-examples to the simplis c asser ons made above are apparent in the HF absorp on seen toward the star- forming region of NGC2146 SE and the HF emission seen toward the non-AGN NGC 3256. But the interpreta on of HF spectra are just now beginning with these discoveries. "Dust Temperature" vs. HF Absorp on for 24 SPIRE –detected galaxies 0.5
NGC 1068 0.4 Absorp on Emission 0.3 Cen A absorp on NGC 4418 0.2 emission F(25 um) / F(60 um) 0.1
Depending on the amount of cold molecular gas in 0. the line of sight to the central con nuum source -0.4 -0.2 0. 0.2 0.4 0.6 (pencil beam) vs. the amount of warm gas in the HF Line/Con nuum (241 um) main beam (19" in diameter) HF may be seen in emission or absorp on. In NGC1068 for example, NGC 6240 the main beam includes the inner region of the Circinus starburst ring, which may account for the strong HF emission seen.