J/ApJ/727/20 The Megamaser Cosmology Project (MCP). III. (Kuo+, 2011)
The Megamaser Cosmology Project. III. Accurate masses of seven supermassive black holes in active galaxies with circumnuclear megamaser disks. Kuo C.Y., Braatz J.A., Condon J.J., Impellizzeri C.M.V., Lo K.Y., Zaw I., Schenker M., Henkel C., Reid M.J., Greene J.E. <Astrophys. J., 727, 20 (2011)> =2011ApJ...727...20K
ADC_Keywords: Active gal. nuclei ; Masers ; Galaxies, radio ; Galaxies, Seyfert Keywords: accretion, accretion disks - galaxies: active - galaxies: ISM - galaxies: nuclei - galaxies: Seyfert Abstract: Observations of H2O masers from circumnuclear disks in active galaxies for the Megamaser Cosmology Project (MCP) allow accurate measurement of the mass of supermassive black holes (BH) in these galaxies. We present the Very Long Baseline Interferometry images and kinematics of water maser emission in six active galaxies: NGC 1194, NGC 2273, NGC 2960 (Mrk 1419), NGC 4388, NGC 6264 and NGC 6323. We use the Keplerian rotation curves of these six megamaser galaxies, plus a seventh previously published, to determine accurate enclosed masses within the central ∼0.3pc of these galaxies, smaller than the radius of the sphere of influence of the central mass in all cases. Description: The megamaser galaxies in our sample were observed between 2005 and 2009 with the Very Long Baseline Array (VLBA), augmented by the 100m Green Bank Telescope (GBT) and in most cases the Effelsberg 100m telescope. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 78 7 The Megamaser sample table3.dat 52 630 Maser spots table4.dat 78 7 The BH masses and basic properties of the maser disks
See also: VIII/77 : HI spectral properties of galaxies (Springob+, 2005) J/A+A/530/A147 : Megamaser detection in Seyfert galaxies (Ramolla+, 2011) J/ApJ/695/276 : Search for megamasers in type-2 AGNs (Bennert+, 2009) J/ApJ/678/96 : Extragalactic H2O masers (Braatz+, 2008) J/AJ/131/1236 : Central black holes of spiral galaxies (Dong+, 2006) J/A+A/435/521 : Radio Sources in Low-Luminosity AGNs. IV (Nagar+, 2005) J/PASJ/55/947 : Blazars and Seyfert galaxies accretion rates (Liang+, 2003) J/ApJS/133/77 : VLA radio continuum survey of Seyfert galaxies (Ho+, 2001) J/ApJS/121/473 : A diagnostic diagram for Seyfert 2 Galaxies (Bassani+, 1999) J/A+AS/130/333 : 2112 new 21-cm line measurements (Theureau+ 1998) J/ApJS/112/315 : Spectroscopic parameters of Seyfert nuclei (Ho+ 1997) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name Galaxy name 10- 11 I2 h RAh Hour of right ascension (J2000) (1) 13- 14 I2 min RAm Minute of right ascension (J2000) 16- 23 F8.5 s RAs Second of right ascension (J2000) 25 A1 --- fp [a-g] Flag on position (2) 27 A1 --- DE- Sign of declination (1) 28- 29 I2 deg DEd Degree of declination (1) 31- 32 I2 arcmin DEm Arcminute of declination 34- 39 F6.3 arcsec DEs Arcsecond of declination 41- 44 F4.1 mas e_RA Uncertainty on right ascension 45 A1 --- fp1 [h] Flag on e_RA (2) 47- 50 F4.1 mas e_DE Uncertainty on declination 51 A1 --- fp2 [h] Flag on e_DE (2) 53- 57 I5 km/s Vsys Systemic (recessional) velocity (3) 59- 60 I2 km/s e_Vsys Vsys uncertainty (4) 62- 67 A6 --- SpT NED Seyfert spectral type 69- 78 A10 --- T NED Hubble morphological type
Note (1): The positions of UGC 3789, NGC 1194, NGC 6323, and NGC 4388 refer to the location of maser emission determined from our VLBI phase-referencing observations. The positions of NGC 2273 and NGC 2960 are determined from K-band VLA A-array observations of continuum emission from program AB1230 and maser emission from AB1090, respectively. The maser position for NGC 6264 is derived from a phase-referencing observation in the VLBA archival data (project BK114A). Note (2): Flag on positions as follows: a = The position of the maser spot at Vop=4684km/s, where Vop is the "optical" velocity of the maser spot relative to the LSR. b = The position of the radio continuum emission observed at 21867.7MHz and 21898.9MHz. c = The position of the maser spot at Vop=2689km/s. d = The position of the maser spot at Vop=4476km/s. e = The position of the maser spot at Vop=2892km/s. f = The average position of the masers with velocities from Vop=10180km/s to Vop=10214km/s g = The position of the maser spot at Vop=7861km/s. h = For all positions derived from VLA observations, we use 10mas as the actual position error, rather than use the fitted error from the VLA data, which are only a few mas for these galaxies. The reason is that the systematic error caused by the imperfect tropospheric model of the VLA correlator can be as large as a few to 10s mas. A 10mas position error usually leads to a ∼3%-5% error in the BH mass for the megamasers presented here. Note that although the position for UGC 3789 is derived from a VLBI phase-referencing observation with a phase calibrator 2.1° away, the position of this calibrator is derived from a VLA observation. So, we also use 10mas as the actual position accuracy for UGC 3789. Note (3): The systemic (recessional) velocities of the galaxies, Vsys, listed here are based on the "optical" velocity convention (i.e., no relativistic corrections are made), measured with respect to the LSR. Except NGC 4388, the systemic velocities Vsys are obtained from fitting a Keplerian rotation curve to the observed data as described in Section 3. Note (4): The uncertainties δVsys given here include both the fitting error and a conservative estimate of the systematic error. The fitting error is typically only about 5km/s and the systematic error is from possible deviation of the position of the BH from (θx, θy)=(0,0) (see Section 3), which is assumed in our rotation curve fitting. For NGC 4388, we adopt the observed HI velocity from Lu et al. (1993ApJS...88..383L), which has a small but perhaps unrealistic error.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name Galaxy name 10- 17 F8.2 km/s Vop Velocity (V_op_) (1) 19- 24 F6.3 mas oRA Right Ascension offset (2) 26- 30 F5.3 mas e_oRA Uncertainty in oRA 32- 37 F6.3 mas oDE Declination offset (2) 39- 43 F5.3 mas e_oDE Uncertainty in oDE 45- 48 F4.1 mJy Flux Fitted peak intensity; mJy/beam 50- 52 F3.1 mJy e_Flux Uncertainty in Flux
Note (1): Referenced to the LSR and using the optical definition (no relativistic corrections). Note (2): East-west and north-south position offsets and uncertainties measured relative to the average position of the systemic maser in the VLBI map (Figure 2). Position uncertainties reflect fitted random error only. In NGC 1194 and NGC 2960 there can be an additional uncertainty caused by the poorer tropospheric delay calibrations because of its low declinations (low elevations during the observations).
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name Galaxy name 10- 14 F5.1 Mpc Dist NED Hubble flow distance 16- 19 F4.2 10+7Msun Mass Measured BH mass 21- 24 F4.2 10+7Msun e_Mass Mass uncertainty (1) 26- 30 F5.3 pc iSize Size of the inner edge of the maser disk 32- 36 F5.3 pc oSize Size of the outer edge of the maser disk 38- 41 I4 deg PA [-131/157] Position angle of the disk plane measured east of north (2) 43 A1 --- l_Incl Limit flag on Incl 44- 45 I2 deg Incl ? Inclination of the maser disk (3) 47- 51 F5.3 pc Radc Core radius of the Plummer cluster (4) 53- 58 E6.2 Msun/pc3 rho0 Central mass density of the Plummer cluster (5) 60- 64 F5.2 Msun mMax Maximum stellar mass of the Plummer cluster (6) 66 A1 --- l_Tage Limit flag on Tage 67- 72 E6.2 yr Tage Lifetime of a cluster (7) 74- 78 F5.3 arcsec Rinf Radius of the gravitational sphere of influence for the maser BH (8)
Note (1): The mass uncertainty here only includes errors caused by source position uncertainty and from fitting a Keplerian rotation curve for a given distance. Except for NGC 4388, the actual BH mass uncertainty is dominated by the error of the latest H0 measurement (∼6%). NGC 4388 has a larger BH mass error (11%) which is limited by the uncertainty of the Tully-Fisher distance determination (see the explanation in Section 3.2). Note (2): P.A. equals zero when the blueshifted side of the disk plane has zero east offset and positive north offset. Note (3): Note that the inclination of NGC 4388 is unconstrained because we did not detect systemic masers. Note (4): For NGC 1194, NGC 2273, NGC 2960, and NGC 4388, the core radii are derived from Equation (12). For UGC 3789, NGC 6264, and NGC 6323, the radii are derived from the Plummer rotation curve fitting. Note (5): ρ0=3M∞/4πr3c. Here, M∞ is obtained from the Plummer rotation curve fitting. Note (6): The maximum stellar mass of the Plummer cluster below which the cluster will not evaporate in less than 10Gyr. In all cases except NGC 1194, a cluster of neutron stars can be directly ruled out because mmax is less than ∼1.4M☉. Note (7): The values shown here are limited by the collision timescale, which is the maximum lifetime of the cluster composed of either main-sequence stars, brown dwarfs, white dwarfs, or neutrons stars. Note (8): We calculate Rinf using Equation (1) of Barth et al. (2004cbhg.symp...21B) with the bulge velocity dispersion measurements from Greene et al. (2010ApJ...721...26G).
History: From electronic version of the journal References: Braatz et al. Paper I. 2009ApJ...695..287R Braatz et al. Paper II. 2010ApJ...718..657B
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Aug-2012
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