J/ApJ/738/27 Galactic HII regions RRL and continuum data (Balser+, 2011) ================================================================================ H II region metallicity distribution in the Milky Way disk. Balser D.S., Rood R.T., Bania T.M., Anderson L.D. =2011ApJ...738...27B ================================================================================ ADC_Keywords: H II regions ; Milky Way ; Radio lines ; Radio continuum Keywords: Galaxy: abundances - H II regions - radio lines: ISM Abstract: The distribution of metals in the Galaxy provides important information about galaxy formation and evolution. HII regions are the most luminous objects in the Milky Way at mid-infrared to radio wavelengths and can be seen across the entire Galactic disk. We used the National Radio Astronomy Observatory (NRAO) Green Bank Telescope to measure radio recombination line (RRL) and continuum emission in 81 Galactic HII regions. We calculated LTE electron temperatures using these data. In thermal equilibrium metal abundances are expected to set the nebular electron temperature with high abundances producing low temperatures. Our HII region distribution covers a large range of Galactocentric radius (5-22kpc) and samples the Galactic azimuth range 330-60{deg}. Using our highest quality data (72 objects) we derived an O/H Galactocentric radial gradient of -0.0383+/-0.0074dex/kpc. Combining these data with a similar survey made with the NRAO 140 Foot telescope we get a radial gradient of -0.0446+/-0.0049dex/kpc for this larger sample of 133 nebulae. Description: We discuss radio recombination line (RRL) and continuum observations at X band (8-10GHz) toward 81 Galactic HII regions with the NRAO Green Bank Telescope (GBT). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 92 81 Properties of Galactic HII regions table2.dat 68 173 Radio recombination line (RRL) parameters of Galactic HII regions table3.dat 93 81 Radio continuum parameters of Galactic HII regions -------------------------------------------------------------------------------- See also: VIII/58 : A Survey of Radio H II Regions in the Northern Sky (Lockman+ 1989) J/ApJS/194/32 : The HII Region Discovery Survey (HRDS). II. (Anderson+, 2011) J/ApJ/690/706 : Distances of Galactic HII regions (Anderson+, 2009) J/A+A/464/909 : JHK photometry near IRAS 06145+1455 (Brand+, 2007) J/ApJS/165/338 : Radio recombination lines in HII regions (Quireza+, 2006) J/ApJ/653/1226 : Physical properties of galactic HII regions (Quireza+, 2006) J/ApJS/162/346 : Abundance gradients in the Galaxy (Rudolph+, 2006) J/ApJ/582/756 : Velocities of HII regions (Kolpak+, 2003) J/A+A/397/213 : Galactic HII regions (Paladini+, 2003) J/ApJ/488/224 : 4.85 GHz fluxes of H II regions (Kuchar+ 1997) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 13 A13 --- Name HII region name 15- 21 F7.3 deg GLON [7/244] Galactic longitude 23- 29 F7.3 deg GLAT [-20/3.5] Galactic latitude 31- 32 I2 h RAh Hour of right ascension (B1950) 34- 35 I2 min RAm Minute of right ascension (B1950) 37- 40 F4.1 s RAs Second of right ascension (B1950) 42 A1 --- DE- Sign of declination (B1950) 43- 44 I2 deg DEd Degree of declination (B1950) 46- 47 I2 arcmin DEm Arcminute of declination (B1950) 49- 52 F4.1 arcsec DEs Arcsecond of declination (B1950) 54- 60 F7.3 deg Az [0/360] Galactocentric azimuth 62- 65 F4.1 kpc Rgal [4.7/21.9] Galactocentric radius 67- 70 F4.1 kpc dsun [0.3/30.3] Distance from the Sun (1) 72- 76 F5.3 --- y [0.017/0.135] Helium abundance ratio by number 78- 82 F5.3 --- e_y y uncertainty 84- 88 I5 K Te [5229/14578] LTE electron temperature 90- 92 I3 K e_Te Te uncertainty -------------------------------------------------------------------------------- Note (1): Kinematic distances are derived using the measured source velocity and a rotation curve model for the Galaxy. For all kinematic distances we use our measured hydrogen RRL velocities (see Table 2) and the Brand J. (1986, PhD thesis, Leiden Univ., Netherlands) rotation curve model. See section 2 for further explanations. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 13 A13 --- Name HII region name 15- 16 A2 --- El Atom (C, H or He) 18- 24 F7.2 mK TL [2.31/9728.44] Peak intensity (T_L_) 26- 30 F5.2 mK e_TL TL uncertainty 32- 36 F5.2 km/s DelV [1.9/42.2] FWHM line width ({Delta}V) 38- 41 F4.2 km/s e_DelV DelV uncertainty 43- 49 F7.2 km/s Vlsr [-107.36/89.84] LSR velocity 51- 54 F4.2 km/s e_Vlsr Vlsr uncertainty 56- 60 F5.1 h Tint [2.4/108.8]? Total integration time (1) 62- 66 F5.2 mK rms ? root-mean-square noise of the line free region 68 A1 --- QF [A-D] Data quality (A=excellent; D=poor) (G1) -------------------------------------------------------------------------------- Note (1): The integration time listed is derived from the spectral average of both polarizations of the H87{alpha}, H88{alpha}, H89{alpha}, H91{alpha}, H92{alpha}, and H93{alpha} transitions. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 13 A13 --- Name HII region name 15- 21 F7.3 K TcRA Peak intensity (T_C_) for the RA scans 23- 27 F5.3 K e_TcRA TcRA uncertainty 29- 33 F5.3 arcmin TheRA FWHM angular width ({Theta}) for the RA scans 35- 39 F5.3 arcmin e_TheRA TheRA uncertainty 41- 47 F7.3 K TcDE Peak intensity (T_C_) for the DEC scans 49- 53 F5.3 K e_TcDE TcDE uncertainty 55- 59 F5.3 arcmin TheDE FWHM angular width ({Theta}) for the DEC scans 61- 65 F5.3 arcmin e_TheDE TheDE uncertainty 67- 73 F7.3 K Tc [0.092/110.79] Average peak intensity (T_C_) 75- 79 F5.3 K e_Tc Tc uncertainty 81- 85 F5.3 arcmin Theta [1.3/7.6] Average FWHM angular width ({Theta}) 87- 91 F5.3 arcmin e_Theta Theta uncertainty 93 A1 --- QF [A-D] Data quality (A=excellent; D=poor) (G1) -------------------------------------------------------------------------------- Global notes: Note (G1): The QF is a measure of data quality taking into account the signal-to-noise ratio, snr, the baselines, confusion, and the Gaussian fit. See section 4 for further details. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Emmanuelle Perret [CDS] 11-Jan-2013