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J/ApJ/695/276       Search for megamasers in type-2 AGNs        (Bennert+, 2009)

A search for H2O megamasers in high-z Type-2 active galactic nuclei. Bennert N., Barvainis R., Henkel C., Antonucci R. <Astrophys. J., 695, 276-286 (2009)> =2009ApJ...695..276B
ADC_Keywords: Active gal. nuclei ; Galaxies, Seyfert ; Radio lines Keywords: galaxies: active - galaxies: Seyfert - masers - quasars: general Abstract: We report a search for H2O megamasers in 274 SDSS type-2 active galactic nuclei (AGNs; 0.3<z<0.83), half of which can be classified as type-2 quasi-stellar objects (QSOs) from their [OIII]5007 luminosity, using the Robert C. Byrd Green Bank Telescope (GBT) and the Effelsberg 100m radio telescope. Apart from the detection of the extremely luminous water vapor megamaser SDSS J080430.99+360718.1, already reported by Barvainis & Antonucci (2005ApJ...628...89B), we do not find any additional line emission. This high rate of nondetections is compared to the water maser luminosity function created from the 78 water maser galaxies known to date and its extrapolation toward the higher luminosities of "gigamasers" that we would have been able to detect given the sensitivity of our survey. The properties of the known water masers are summarized and discussed with respect to the nature of high-z type-2 AGNs and megamasers in general. In the Appendix (tables 4 and 5), we list 173 additional objects (mainly radio galaxies, but also QSOs and galaxies) that were observed with the GBT, the Effelsberg 100m radio telescope, or Arecibo Observatory without leading to the detection of water maser emission. Description: All sources were measured in the 616-523 line of H2O (22.23508GHz rest frequency). The observations were carried out during several runs at the GBT of the National Radio Astronomy Observatory (NRAO) in 2005 January and June as well as at the Effelsberg 100m radio telescope of the Max-Planck-Institut fur Radioastronomie (MPIR) in 2005 November and December. For details of observations, see table 1. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 84 288 Details of observations: 274 SDSS type-2 AGNs table2.dat 121 83 The 78 galaxies at D≥100kpc with known H2O masers table4.dat 99 148 Details of observations: radio galaxies table5.dat 99 26 Details of observations: miscellaneous sources refs.dat 63 52 References for table 2
See also: VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010) VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010) VII/113 : Catalogued Galaxies + QSOs observed in IRAS, V2 (IPAC, 1989) J/ApJ/678/96 : Extragalactic H2O masers (Braatz+, 2008) J/ApJ/658/1096 : H2O maser classification (Deacon+, 2007) J/PASJ/59/1185 : Water maser in galactic IRAS sources (Sunada+, 2007) J/ApJ/652/136 : Water maser emission in five AGNs (Kondratko+, 2006) J/MNRAS/362/9 : Radio-loud AGN in SDSS (Best+, 2005) J/AJ/128/1002 : SDSS candidate type II quasars. II (Zakamska+, 2004) J/AJ/126/2125 : SDSS candidate type II quasars (Zakamska+, 2003) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 18 A18 --- SDSS Source identification (1) 20- 24 F5.3 --- z Heliocentric redshift (2) 26- 29 F4.2 [Lsun] L[OIII] Log of [OIII] luminosity (3) 31- 37 F7.2 mJy F20cm ? FIRST 20cm integrated flux (4) 39 A1 --- f_F20cm [n] 'n' if field not observed by FIRST survey 41- 48 F8.2 MHz nu Observed frequency 50- 53 F4.1 mJy rms Root mean square flux density 55- 59 I5 km/s vmin Minimum velocity covered by observation 61- 64 I4 km/s vmax Maximum velocity covered by observation 66- 68 F3.1 km/s dv Channel width 70- 79 A10 --- Tel Telescope used (G1) 81- 84 I04 --- Epoch Date of observation in MMYY format
Note (1): Where the source position is given in the identification in the format HHMMSS.ss+DDMMSS.s. Note that only in first object was megamaser emission detected (Barvainis & Antonucci, 2005ApJ...628...89B) Note (2): From Zakamska et al. (2003, Cat. J/AJ/126/2125) as measured from the [OII]3727 emission line. Note (3): From Zakamska et al. (2003, Cat. J/AJ/126/2125). A value >8.48 classifies the object as a type-2 QSO. Note (4): From Zakamska et al. (2003, Cat. J/AJ/126/2125), if the object is matched within 3". There is no entry if the object was not detected, i.e. <1mJy.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 16 A16 --- Name Source name 18- 25 A8 --- OName Other name 27 A1 --- f_Name [ad] Note for NGC 598 (1) 29- 30 I2 h RAh Hour of right ascension (J2000) 32- 33 I2 min RAm Minute of right ascension (J2000) 35- 38 F4.1 s RAs Second of right ascension (J2000) 40 A1 --- DE- Declination sign (J2000) 41- 42 I2 deg DEd Degree of declination (J2000) 44- 45 I2 arcmin DEm Arcminute of declination (J2000) 47- 48 I2 arcsec DEs Arcsecond of declination (J2000) 50- 54 I5 km/s cz ? Systemic velocity from NED 55 A1 --- f_cz [z] For SDSS J0804+3607, z=0.66 57- 63 F7.2 Mpc Dist ? Distance (2) 65- 68 F4.1 [Lsun] LFIR ? Far_infrared (FIR) luminosity (log(LFIR/L)) (3) 69 A1 --- f_LFIR [bhi] lower limit or missing measurements (4) 71- 73 I3 K Tdust ? Dust temperature (4)(3) 75- 78 F4.1 [Lsun] LH2O H2O luminosity (log(LH2O/L), using H0=75km/s/Mpc 79 A1 --- f_LH2O [cef] Note on LH2O computation (5) 81- 94 A14 --- Mtype Host galaxy morphological type from NED 95 A1 --- f_Mtype [j] Flag on Mtype (6) 97-108 A12 --- Otype Activity type from NED (7) 109 A1 --- f_Otype [g] Flag on Otype (8) 111-121 A11 --- Ref Reference(s) number(s); see refs.dat file
Note (1): Flag as follows: a = While the detection of two more masers has been claimed by Huchtmeier et al. (1978A&A....64L..21H, 1988A&A...200...26H), we list only the three masers confirmed by Brunthaler et al. (2006A&A...457..109B). d = The maser luminosity refers to a brief flaring episode. Note (2): Using H0=75km/s/Mpc. For the 53 of the 78 masers that were included in Henkel et al. (2005A&A...436...75H), we adapt the distances from their table 4. For a few objects, we take distances from the references listed in Column "Ref". Note (3): For the determination of LFIR and Tdust (60/100um color temperatures), see Wouterloot & Walmsley (1986A&A...168..237W). The IRAS fluxes were taken from Fullmer & Lonsdale (1989, Cat. VII/113) and, for a few sources (NGC 262, NGC 598, IC 0184, NGC 4151, NGC 4258, IRAS F19370-0131, NGC 6323, 3C 403, and AM 2158-380b), from NED. Note (4): Flag as follows: b = LFIR and Tdust are lower limits as there are no IRAS flux measurements at 12 and 25um. h = There is no IRAS flux measurement at 12um. i = There is no IRAS flux measurement at 100um. Note (5): Flag as follows: c = Estimated from Figure 1 of Kondratko et al. (2006, Cat. J/ApJ/652/136) using LH2O/L=0.023Stotal/(Jy.km/s)*D2/Mpc with Stotal=Σ(1.06Speak*FWHM) (summed over the different components). e = We assume logLH2O/L=0.9 as total integrated single-dish flux density when including NGC 2146 in Figures 1, 2, and 3. f = Using H0=75km/s/Mpc, ΩΛ=0.73, and ΩM=0.27. Note (6): j = Note that while NED lists "E/S0" as morphological classification of the host galaxy according to Koekemoer et al., 1995Natur.378..697K, Falcke et al. (2000ApJ...530L..13F) favor a classification as a highly inclined spiral galaxy. We use the latter in our statistics in Section 5. Note (7): Types as follows: Sy = Seyfert, L = LINER, LIRG = luminous-infrared galaxy, SB = starburst, NLRG = narrow-line radio galaxy, RG = radio galaxy Note (8): g = Note that NED gives "Sy3" as classification, which corresponds to a LINER (Veron-Cetty & Veron 1996, Cat. VII/258).
Byte-by-byte Description of file: table[45].dat
Bytes Format Units Label Explanations
1- 23 A23 --- Name Source identification 25- 27 A3 --- Class NED Classification (for table 5 only) 29- 30 I2 h RAh NED Hour of Right Ascension (J2000) 32- 33 I2 min RAm NED Minute of Right Ascension (J2000) 35- 38 F4.1 s RAs NED Second of Right Ascension (J2000) 40 A1 --- DE- Sign of the NED Declination (J2000) 41- 42 I2 deg DEd NED Degree of Declination (J2000) 44- 45 I2 arcmin DEm NED Arcminute of Declination (J2000) 47- 48 I2 arcsec DEs NED Arcsecond of Declination (J2000) 50- 54 F5.3 --- z NED Heliocentric redshift 56- 63 F8.2 MHz nu Observed frequency 65- 68 F4.1 mJy rms Root mean square flux density 70- 74 I5 km/s vmin Minimum velocity covered by observation 76- 79 I4 km/s vmax Maximum velocity covered by observation 81- 83 F3.1 km/s dv Channel width 85- 94 A10 --- Tel Telescope used (G1) 96- 99 I04 --- Epoch Date of observation in MMYY format
Byte-by-byte Description of file: refs.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Ref Reference number 4- 22 A19 --- BibCode Bibcode 24- 44 A21 --- Aut Author's name 46- 63 A18 --- Com Catalog reference in VizieR
Gloval Notes: Note (G1): Telescope as follows: GBT = Robert C. Byrd Green Bank Telescope; Arecibo = Arecibo Observatory; Effelsberg = Effelsberg 100-m radio telescope.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 19-Apr-2011
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