[OI] and [NII] Observations of Relevance to STO Gordon Stacey

[NII] Lines Density tracer for low density ionized gas Proxy for Lyman continuum flux Determines [CII] fraction from ionized gas [NII] has two transitions –Both these lines relatively unexplored –122  m line somewhat challenging from airplane –205  m line at long wavelength end of photoconductors –Lines are strong – fair number of ISO LWS observations of 122  m line –2 KAO observations using the CGS of both lines (M82 and G ) –Large beam COBE observations of 205  m line –Ground based 205  m line observations N+N+ 3P23P2 3P13P1 3P03P0 70 K 188 K 0 K 122 um 205 um

[OI] Lines Many observations of these lines from Galactic and extra-galactic sources KAO/ISO LWS Very strong lines in general –[OI]/[CII] typically ½ –[OI] 63/146 ~ 15-20:1 O0O0 3P03P0 3P13P1 3P23P2 228 K 327 K 0 K 146 um 63 um

COBE Large (7.2  ) beam –What is the scale height? –PDR or ionized gas [CII]/[NII] 205 ~ 10:1 [CII]/[NII] 122 ~ 6:1 Argue for 27% of [CII] from ionized gas

[NII] 205  m Line: Carina Nebula [NII] 205  m line from in the Carina Nebula with SPIFI on AST/RO at South Pole (Oberst et al. 2006) [NII] 122/205  m line ratio ~ 1.8: 1  n e ~ 30 cm -3 [CII]/[NII] ratio ~ 9:1, predicted ratio ~ 2.4:1  27% of [CII] originates from ionized gas

Observations of Candidate Sources M17 KAO: Meixner et al –Peak ~ 1.3  erg/s/cm 2 /sr –Beam ~ 36” ISO: Henning et al A&A 332, 1035 –Just one spectrum presented –[OI] and [NII] lines detected

Other Candidates MBM12 – nearby starformation region –Haven’t found much yet – Mark Wolfire found [CII] Polaris Flare –Again, haven’t found much ISO data yet Carina Neb ula –SPIFI-AST/RO map of [NII] over > 10’ square region with 55” beam –ISO [NII] 122  m, [OI] and [CII] data available and published (Mizutani et al. 2002, 2004)

DR21 in Cygnus KAO [OI] 63  m line obtained over inner 2.5’ (Poglitsch et al. 1996) – 25” beam ISO LWS spectroscopy available and published in Jakob et al including [NII] and [OI] lines Position [C II][O I] [O III] [N II] I[10 -4 erg s -1 cm -2 sr -1 ]158 um63 um145 u m 52 um 88 u m 122 u m DR21 E DR21 C <0.75 DR21 W DR21 (OH) (1.27)1.56<2.7 DR21 FIR <0.6

Galactic Plane Surveys Not really any dedicated surveys in [OI] or [NII] save COBE FIRAS However there has been work on the ISO data set – collecting all the observations

ISO Study of the Diffuse ISM Searched the ISO archive and find there are about 500 LO1 spectra of Galactic LOS w/o known energetic sources LWS01: 47 to 196  m –[OI] 63 and 145  m –[CII] 158  m –[NII] 122  m Current study contains 144 LOS w/ l <10 

Three Regions Defined Galactic Center Inner Outer 100 um continuum flux (33 Jy) Galactic Longitude (abs. value)

Dust color temperature Plot is 100/160 vs. 62.5/100 continuum ratios Tracks are grey body temps for  = 0 an 1.5 Shift below  = 0 is likely due to hot small grain contribution at 63.5  m (40% in inner galaxy and 60% in outer galaxy Color temps and  need to be corrected for this effect

Atomic Fine Structure Lines Excellent correlation between the line intensities and far-IR continuum

Line Ratios Low continuum (33 Jy/beam) –[CII]/[NII] ~ 3.6:1 –[OI](63)/[CII] ~ 1:3 –[OI](63)/[OI] 146 ~ 15:1 High continuum (3300 Jy/beam) –[CII]/[NII] ~ 13:1 –[OI](63)/[CII] ~ 1:2.5 –[OI](63)/[OI] 146 ~ 8.5:1 Larger PDR contribution in brighter regions Not much (1/6) [CII] from ionized gas Optically thick or forground absorbed 63  m line