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The ultraviolet and optical spectra of many galaxies contain emission lines produced by ionized gas. Identification of the ions associated with emission lines provides insight into the nature of the ionizing source. In most cases, the ionizing source is safely assumed or observed directly to be ultraviolet photons created by large populations of hot O and B stars. In other cases, the presence of lines associated with high-ionization species such as [Fe X] is a clear indicator of ionization processes unrelated to photoionization by hot stars. Such lines often serve as the sole source of information on that which by definition cannot be observed directly.

This page tabulates wavelengths and atomic transition data for emission lines from 700-11,000Å that have historically been observed in the spectra of galaxies, active galactic nuclei (AGN), and quasi-stellar objects (QSOs). This page does not theorize on lines that could or should be observed in such objects - only lines that have been observed are listed. References to journal papers where lines were identified are provided in the final column. These references are not intended to be exhaustive (I simply list the first paper where I found a line being identified, preferably with a plot of the spectrum clearly shown). Full 'Observation References' are here.

Transition data (columns 1-8) from the NIST Atomic Spectra database are used with permission from John Curry, Director of the NIST Atomic Spectroscopy Data Center (full citation here). Note that semi-forbidden/intercombination notation (for example, O IV]) is used to indicate transitions which violate the ΔS=0 rule. Also, fine and hyperfine structure for H transitions are excluded for now, while links to snapshots of data on blended He I and He II transitions are provided. Given sufficient literature evidence, data for all contributions to blends of two or three lines are provided.

Vacuum wavelengths are given for lines with λ < 2000Å; air wavelengths are given for lines with λ > 2000Å. 'Creation' ionization potentials are provided (i.e. 207.27 eV is necessary to ionize Ne VII and create Ne VIII).

>> Note:

* This page is a work in progress, and is subject to change. Please e-mail me if I need to correct something or add emission lines to the table.

>> Observation References:

• FO87: Ferland & Osterbrock 1987 (III Zw 77)
• OP85: Osterbrock & Pogge 1985 (NLSy1 galaxies)
• R11: Rose et al 2011 (SDSS 1131+16)
• K08: Komossa et al 2008 (SDSS 0952+21)
• A92: Alloin et al 1992 (ESO 138 G1)
• W11: Wang et al 2011 (SDSS 0748+47)
• I04: Izotov et al 2004 (Tol 1214-277 and Tol 65)
• I01: Izotov et al 2001 (SBS 0335-052)
• P98: Puchnarewicz et al 1988 (RE J1034+396)
• TI05: Thuan & Izotov 2005 (Blue compact dwarfs)
• LM04: Leighly & Moore 2004 (STIS study of NLSy1 galaxies)
• T00: Tran et al 2000 (Keck - P09104+4109)
• Z97: Zheng et al 1997 (HST quasar composite)
• VB01: Vanden Berk et al 2001 (SDSS quasar composite)
• OC82: Osterbrock and Cohen 1982 (Wolf-Rayet galaxies)
• S99: Shaerer et al 1999 (Wolf-Rayet Galaxies)
• P88: Persson 1988 (Ca triplet emission in AGN)
• D06: Dhanda et al 2006
• OF96: Osterbrock & Fulbright 1996 (NGC 1068)
• O90: Osterbrock et al 1990

 

>> Transition Data Reference:

Ralchenko, Yu., Kramida, A.E., Reader, J. and NIST ASD Team (2010). NIST Atomic Spectra Database (version 4.0), [Online]. Available: http://physics.nist.gov/asd [Tuesday, 20-Sep-2011 13:19:04 EDT]. National Institute of Standards and Technology, Gaithersburg, MD.

>> Transition Data Note:

I take no credit whatsoever for the data shown in all but the last column of the table. All credit goes to the members of the NIST ASD Team, to whom I am grateful for assembling such an extensive and detailed database of atomic transition data. The entire team is listed below, and to each member I say THANKS!

Principal Developers (Currently Active):

Yu. Ralchenko,¹ A.E. Kramida,¹ and J. Reader¹


Data Compilers (Currently Active):
   Atomic Energy Levels and Wavelengths:

A.E. Kramida,¹ E.B. Saloman,¹ J.E. Sansonetti,¹ and J.J. Curry¹


   Atomic Transition Probabilities:

D.E. Kelleher,¹ A.E. Kramida,¹ J.R. Fuhr,¹ L. Podobedova,¹ and W.L. Wiese¹


Database Developers (Currently Active):
   Database Management:

Yu. Ralchenko,¹ A.E. Kramida,¹ and K. Olsen²


   World Wide Web Interface:

Yu. Ralchenko¹


Past Contributors:

G.R. Dalton,³ R. Dragoset,² F.-C. Jou,¹ W.C. Martin,¹ P.J. Mohr,¹  A. Musgrove,¹ C.J. Sansonetti,¹ and G. Wiersma²

 

¹Atomic Physics Division
²Office of ECSED
³Standard Reference Data Program