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J/AJ/121/97         K-band spectroscopy of ULIRGs            (Murphy+, 2001)

K-band spectroscopy of ultraluminous infrared galaxies: the 2 Jy sample. Murphy T.W.JR, Soifer B.T., Matthews K., Armus L., Kiger J.R. <Astron. J., 121, 97-127 (2001)> =2001AJ....121...97M
ADC_Keywords: Galaxies, IR ; Galaxies, spectra Keywords: Galaxies: Active, Galaxies: Starburst Abstract: We present near-infrared spectroscopy for a complete sample of 33 ultraluminous infrared galaxies at a resolution of R∼1000. Most of the wavelength range from 1.80-2.20µm in the rest frame is covered, including the Paα and Brγ hydrogen recombination lines, and the molecular hydrogen vibration-rotation 1-0 S(1) and S(3) lines. Other species, such as He I, [Fe II], and [Si VI] appear in the spectra as well, in addition to a number of weaker molecular hydrogen lines. Nuclear extractions for each of the individual galaxies are presented here, along with spectra of secondary nuclei, where available. The Paα emission is seen to be highly concentrated on the nuclei, typically with very little emission extending beyond a radius of 1kpc. This survey was carried out primarily to search for signatures of active nuclei via velocity-broadened hydrogen recombination or the presence of the [Si VI] coronal line. These signatures are rare in the present sample, occurring in only two of the 33 galaxies. The extinction to the hydrogen recombination lines is investigated via the Paα/Brγ line ratio. It is found that visual extinctions to the nuclei in excess of 10mag are relatively common among ULIRGs and that visual extinctions greater than 25mag are necessary to conceal a QSO emitting half the total bolometric luminosity. The ionized hydrogen regions in many ULIRGs are sufficiently obscured that dust-enshrouded active galactic nuclei would remain hidden at 2µm at the current level of sensitivity. The vibration-rotation lines of molecular hydrogen appear to be predominantly thermal in origin, with effective temperatures generally around 2200K. The relative nuclear velocities between double nucleus ULIRGs are investigated, through which it is inferred that the maximum deprojected velocity difference is ∼200km.s-1. This figure is lower than the velocities predicted by physical models of strong interactions/mergers of large, gas-rich galaxies. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 37 33 Spectroscopic Survey Sample table5.dat 57 33 Derived Properties table6.dat 30 12 Relative Nuclear Radial Velocities table7.dat 29 15 Physical Parameters of H2 Transitions table8.dat 40 15 Expected H2 Line Strengths
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 15 A15 --- Name Galaxy Name 17- 18 A2 --- n_Name Note (1) 20- 24 I5 km/s cz Galaxy redshift 26- 30 F5.2 [solLum] LumIR IR luminosity in solar units 32- 35 F4.1 arcsec Sep ? Separation of nuclei 37 A1 --- n_Sep [SD] Nucleus structure (2)
Note (1): b = Galaxies with ``warm'' infrared colors: Fν(25um)/Fν(60um) > 0.2; c = Contained in the Bright Galaxy Sample (BGS) of Soifer et al. 1987 (1987ApJ...320..238S). Note (2): S = Denotes a single nucleus; D = Denotes a double nucleus system for which only the primary nucleus spectrum is presented, generally because the separation exceeds the slit length.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 15 A15 --- Name Galaxy name 17- 21 F5.1 mag Av Extinction based on Paα/Brγ 23- 26 F4.1 mag e_Av Uncertainty in Av 28 A1 --- f_Av [d] Indicates apertures for the Paα & Brγ spectral extractions differ by at least 50% 30 A1 --- l_Trot Limit flag on Trot 31- 34 I4 K Trot H2 line rotational temperature 36- 38 I3 K e_Trot ? Uncertainty in Trot 40- 43 I4 K Tvib ? H2 line vibrational temperature (1) 45- 48 I4 K e_Tvib ? Uncertainty in Tvib 50- 57 A8 --- Mech H2 excitation Mechanism (2)
Note (1): Given only for definite thermal/fluorescent mixtures and for likely mixtures (when both of the observed 2-1 lines are above the rotation temperature prediction). The vibration temperature assumes an ortho-to-para ratio of 2:1 in the 2-1 transition states. Note (2): thermal = Classified as consistent with purely thermal; mixture = Classified as definite mixture of thermal and fluorescence; thermal* = Classified as possible mixture of thermal and fluorescence.
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 15 A15 ---- Name Galaxy name 17- 20 I4 km/s Vel Relative velocity 22- 23 I2 km/s e_Vel Uncertainty in Vel 25 A1 --- f_Vel Flag on Vel (1) 27- 30 F4.1 kpc Sep Projected separation
Note (1): From Murphy et al. 2000b (2000AJ....120.1675M). The current data set yields -22±169.
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Trans H2 transition 10- 16 F7.5 um Wave Wavelength in air 18 I1 --- J1 The J1 rotation state 20- 23 F4.2 10-7/s Prob Transition probability from Turner, Kirby-Docken, & Dalgarno 1977 25- 29 I5 K E1/k Energy divided by the Boltzmann constant from Dabrowski 1984
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Trans H2 transition (1) 10- 16 F7.5 um Wave Wavelength in air 18- 22 F5.3 --- S15 H2 line strength relative to H2 1-0 S(1) at Trot=1500 K 24- 28 F5.3 --- S20 H2 line strength relative to H2 1-0 S(1) at Trot=2000 K 30- 34 F5.3 --- S25 H2 line strength relative to H2 1-0 S(1) at Trot=2500 K 36- 40 F5.3 --- S40 H2 line strength relative to H2 1-0 S(1) at Trot=4000 K
Note (1): This table assumes that T{rot}=0.8T{vib}. To recover a strictly thermal regime (T{rot}=T{vib}=T), multiply the 2-1 transitions by exp(-1107/T) and the 3-2 transition by exp(-2144/T).
History: From electronic version of the journal * 08-May-2005: IRAS 14352-1954 has been corrected into IRAS 14351-1954
(End) Greg Schwarz [AAS], Laurent Cambresy [CDS] 22-Jul-2004
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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