The physical properties and excitation mechanisms of H[2] and [Fe II] emission in AGN

Details The physical properties and excitation mechanisms of H[2] and [Fe II] emission in AGN The physical properties and excitation mechanisms of H[2] and [Fe II] emission in AGN

Jun 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006rmxac..26r.206r&link_type=abstract

XI IAU Regional Latin American Meeting of Astronomy (Eds. L. Infante & M. Rubio) Revista Mexicana de Astronomía y Astrofísica (S

Astronomy and Astrophysics

Astronomy

Scientific paper

One of the fundamental problems in AGN and SB galaxies is to determine the dominant excitation mechanisms of the narrow line emitting gas, whether it is due to non-stellar processes or to stellar processes. This ambiguity is most evident when interpreting the spectra of low-ionization lines such as [Fe II] and H_2 lines. Using NIR spectroscopy we study the kinematics and excitation mechanisms of H_2 and [Fe II] lines in a sample of 25 Sy, 17 Sy and 2 SB galaxies, taken on IRTF, using SpeX spectrometer. The spectral coverage allows simultaneous observation of the JHK bands. The H_2 lines are sistematically narrower than the NLR lines, suggesting that the H_2 does not originate from the same parcel of gas that forms the NLR. Emission line ratios between H_2 lines favor thermal excitation mechanisms for the molecular gas in AGN. The mass of hot H_2 ranges from 10^2M&sun; to 10^3M&sun;, with nearly half of objects showing values of < 500M&sun;. It shows that the fraction of molecular mass present in the nuclear region and emitting in the NIR is a very small fraction of the warm molecular mass present in the centre. A diagnostic diagram composed of the line ratios H_2/Brγ and [Fe II]/Paβ probes to be a uselful tool in the NIR for separating emission line objects by their degree of nuclear activity. We found that AGNs are characterized by H_2 2.121μm/Brγ and [Fe II] 1.257μm/Paβ flux ratios between 0.6 and 2. Starburst/H II galaxies display line ratios < 0.6 while LINERS are characterized by values larger than 2 in either ratio.

Affiliated with

Also associated with

No associations

Rating

The physical properties and excitation mechanisms of H[2] and [Fe II] emission in AGN does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The physical properties and excitation mechanisms of H[2] and [Fe II] emission in AGN, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The physical properties and excitation mechanisms of H[2] and [Fe II] emission in AGN will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1479799