J/ApJ/890/118 Megamaser Cosmology Project. XI. Z74-64 VLBI obs. (Pesce+, 2020)
The Megamaser Cosmology Project.
XI. A geometric distance to CGCG 074-064.
Pesce D.W., Braatz J.A., Reid M.J., Condon J.J., Gao F., Henkel C.,
Kuo C.Y., Lo K.Y., Zhao W.
<Astrophys. J., 890, 118 (2020)>
=2020ApJ...890..118P 2020ApJ...890..118P
ADC_Keywords: Active gal. nuclei; Masers; Interferometry; Radial velocities
Keywords: Active galactic nuclei ; Megamasers ; Water masers ;
Supermassive black holes ; Very long baseline interferometry
Abstract:
As part of the survey component of the Megamaser Cosmology Project, we
have discovered a disk megamaser system in the galaxy CGCG 074-064.
Using the Green Bank Telescope and the Very Large Array, we have
obtained spectral monitoring observations of this maser system at a
monthly cadence over the course of two years. We find that the
systemic maser features display line-of-sight accelerations of
∼4.4km/s/yr that are nearly constant with velocity, while the
high-velocity maser features show accelerations that are consistent
with zero. We have also used the High-Sensitivity Array to make a
high-sensitivity very long baseline interferometric map of the maser
system in CGCG 074-064, which reveals that the masers reside in a
thin, edge-on disk with a diameter of ∼1.5mas (0.6pc). Fitting a
three-dimensional warped disk model to the data, we measure a black
hole mass of 2.42-0.20+0.22x107M☉ and a geometric distance
to the system of 87.6-7.2+7.9Mpc. Assuming a cosmic microwave
background-frame recession velocity of 7308±150km/s, we constrain
the Hubble constant to H0=81.0-6.9+7.4(stat.)±1.4(sys.)km/s/Mpc.
Description:
We used the Very Long Baseline Array (VLBA), augmented with the Robert
C. Byrd Green Bank Telescope (GBT) and the phased Karl G. Jansky Very
Large Array (VLA), to map the maser system in CGCG 074-064.
We performed ∼monthly spectral monitoring observations of CGCG074-064
from 2015 October through 2017 May, for a total of 20 epochs. Sixteen
of the monitoring spectra were taken with the GBT. See Section 2.1.
We used the VLA to observe during the 2016 summer months, when the
level of atmospheric water vapor at the Green Bank site would have
made K-band observations inefficient. In total, 4 3hr tracks were
covered by the VLA. See Section 2.2.
In total, we observed 10 6hr VLBI tracks from 2016 January through
2016 June. See Section 2.3.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
14 03 04.46 +08 56 51.0 CGCG 074-064 = Z 74-64
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 78 165 Measurements for individual maser spots
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
J/ApJ/659/1040 : VLBI monitoring of NGC 4258 (Argon+, 2007)
J/ApJ/689/108 : MASIV survey. II. First four epochs (Lovell+, 2008)
J/ApJ/727/20 : The Megamaser Cosmology Project (MCP). III. (Kuo+, 2011)
J/AJ/149/171 : 2MASS galaxy group catalog (Tully, 2015)
J/ApJ/817/128 : Megamaser Cosmology Project. VIII. NGC5765B (Gao+, 2016)
J/ApJ/834/52 : The Megamaser Cosmology Project (MCP). IX. (Gao+, 2017)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 A1 --- Type Spot type (1)
3- 9 F7.2 km/s RV [6007/7776] Radial velocity in the optical,
barycentric reference frame (2)
11- 17 F7.5 Jy Snu [0.0012/0.142] Maser flux density in
VLBI channel maps
19- 25 F7.5 Jy e_Snu [0.0001/0.0008] Uncertainty in Snu
27- 35 F9.6 mas X [-0.832/1.076] Cartesian x coordinate (3)
37- 44 F8.6 mas e_X [0.001/0.025] Uncertainty in X
46- 54 F9.6 mas Y [-0.26/0.33] Cartesian y coordinate (3)
56- 63 F8.6 mas e_Y [0.0029/0.07] Uncertainty in Y
65- 70 F6.3 km/s/yr a [-1.7/7.5] Measured or modeled acceleration
72- 76 F5.3 km/s/yr e_a [0.14/3.4] Associated uncertainty
from the disk modeling
78- 78 I1 --- f_a [0/1] Acceleration type; 1=measured; 0=modeled
--------------------------------------------------------------------------------
Note (1): Spot type as follows:
b = blueshifted (49 occurrences)
s = systemic (45 occurrences)
r = redshifted (71 occurrences)
Note (2): The conversion from barycentric to CMB frame velocities is
vCMB=vbary+263.3km/s for CGCG 074-064 (see Section 1).
Note (3): Positional offset from X,Y in milli-arcseconds, from the absolute
position of the maser system defined as the intensity-weighted mean
position of all systemic maser features to be:
RA(J2000)=14:03:04.457746,DE(J2000)=+08:56:51.03483.
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History:
From electronic version of the journal
References:
Reid et al. Paper I. 2009ApJ...695..287R 2009ApJ...695..287R
Braatz et al. Paper II. 2010ApJ...718..657B 2010ApJ...718..657B
Kuo et al. Paper III. 2011ApJ...727...20K 2011ApJ...727...20K Cat. J/ApJ/727/20
Reid et al. Paper IV. 2013ApJ...767..154R 2013ApJ...767..154R
Kuo et al. Paper V. 2013ApJ...767..155K 2013ApJ...767..155K
Kuo et al. Paper VI. 2015ApJ...800...26K 2015ApJ...800...26K
Pesce et al. Paper VII. 2015ApJ...810...65P 2015ApJ...810...65P
Gao et al. Paper VIII. 2016ApJ...817..128G 2016ApJ...817..128G Cat. J/ApJ/817/128
Gao et al. Paper IX. 2017ApJ...834...52G 2017ApJ...834...52G Cat. J/ApJ/834/52
Zhao et al. Paper X. 2018ApJ...854..124Z 2018ApJ...854..124Z Cat. J/ApJ/854/124
Pesce et al. Paper XI. 2020ApJ...890..118P 2020ApJ...890..118P This catalog
Kuo et al. Paper XII. 2020MNRAS.498.1609K 2020MNRAS.498.1609K
Pesce et al. Paper XIII. 2020ApJ...891L...1P 2020ApJ...891L...1P
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Jul-2021