J/ApJ/851/76 Molecular transitions toward NGC5128 with ALMA (McCoy+, 2017)
ALMA observations of the physical and chemical conditions in Centaurus A.
McCoy M., Ott J., Meier D.S., Muller S., Espada D., Martin S., Israel F.P.,
Henkel C., Impellizzeri V., Aalto S., Edwards P.G., Brunthaler A.,
Neumayer N., Peck A.B., van der Werf P., Feain I.
<Astrophys. J., 851, 76 (2017)>
=2017ApJ...851...76M 2017ApJ...851...76M
ADC_Keywords: Galaxies, nearby; Interferometry; Millimetric/submm sources;
Interstellar medium; Molecular data
Keywords: astrochemistry ; galaxies: active ; galaxies: structure ;
galaxies: elliptical and lenticular, cD ;
galaxies: individual (NGC 5128, Centaurus A) ; galaxies: ISM ;
Abstract:
Centaurus A, with its gas-rich elliptical host galaxy, NGC 5128, is
the nearest radio galaxy at a distance of 3.8Mpc. Its proximity allows
us to study the interaction among an active galactic nucleus, radio
jets, and molecular gas in great detail. We present ALMA observations
of low-J transitions of three CO isotopologues, HCN, HCO+, HNC, CN,
and CCH toward the inner projected 500pc of NGC 5128. Our observations
resolve physical sizes down to 40pc. By observing multiple chemical
probes, we determine the physical and chemical conditions of the
nuclear interstellar medium of NGC 5128. This region contains
molecular arms associated with the dust lanes and a circumnuclear disk
(CND) interior to the molecular arms. The CND is approximately 400pc
by 200pc and appears to be chemically distinct from the molecular
arms. It is dominated by dense gas tracers while the molecular arms
are dominated by 12CO and its rare isotopologues. The CND has a
higher temperature, elevated CN/HCN and HCN/HNC intensity ratios, and
much weaker 13CO and C18O emission than the molecular arms. This
suggests an influence from the AGN on the CND molecular gas. There is
also absorption against the AGN with a low velocity complex near the
systemic velocity and a high velocity complex shifted by about 60km/s.
We find similar chemical properties between the CND in emission and
both the low and high velocity absorption complexes, implying that
both likely originate from the CND. If the HV complex does originate
in the CND, then that gas would correspond to gas falling toward the
supermassive black hole.
Description:
Observations were taken with ALMA during Cycle 0 early science
observing under the project code 2011.0.00010.S (PI:Ott). We observed
20 spectral windows, four in the 1mm band (ALMA Band 6), and 16 in the
3mm band (ALMA Band 3).
The 1mm observations were carried out in a single run with 17 antennas
in a compact configuration on 2012 January 24, with baselines of 18m
to 125m. The 3mm band observations were taken in multiple runs
spanning the time between 2012 April 7 and 2012 May 9 in a more
extended configuration with baselines of 36m to 400m.
Additional ALMA data obtained during science verification
(2011.0.00008.SV) were used to provide the 12CO(2-1) 1.3mm
transition for comparison.
Objects:
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RA (ICRS) DE Designation(s)
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13 25 27.62 -43 01 08.8 NGC 5128 = NAME Centaurus A
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 88 220 Properties of emission components
table3.dat 105 22 Ratios of selected molecular transitions
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See also:
J/A+A/412/657 : CO in cooling flow of clusters of galaxies (Salome+, 2003)
J/A+A/532/A117 : AMIGA VIII. Flux ratio asymmetry parameter (Espada+, 2011)
J/A+A/573/A111 : Group-dominant elliptical galaxies CO sp. (O'Sullivan+, 2015)
J/A+A/593/A118 : HCN(1-0) cube for the nucleus of M51 (Querejeta+, 2016)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Line Line identifier
5- 5 A1 --- f_Line [b] b: Line attributed to the circumnuclear
disk (CND)
7- 8 I2 h RAh [13] Hour of Right Ascension (J2000)
10- 11 I2 min RAm [25] Minute of Right Ascension (J2000)
13- 18 F6.3 s RAs [26.8/28.6] Second of Right Ascension (J2000)
20 A1 --- DE- [-] Sign of the Declination (J2000)
21- 22 I2 deg DEd [43] Degree of Declination (J2000)
24- 25 I2 arcmin DEm [01] Arcminute of Declination (J2000)
27- 32 F6.3 arcsec DEs [0.3/21.6] Arcsecond of Declination (J2000)
34- 44 A11 --- Trans Transition
46 A1 --- l_Peak The 1σ limit flag on Peak
48- 51 F4.2 K Peak [0.01/2.2] Peak temperature
53- 56 F4.2 K e_Peak [0.01/0.2]? Uncertainty in Peak
58- 62 F5.1 km/s Cen [359/727]? Line center
64- 67 F4.1 km/s e_Cen [0.2/12]? Uncertainty in Cen
69- 73 F5.1 km/s FWHM [2/105]? Full-Width at Half-Maximum of line
75- 78 F4.1 km/s e_FWHM [0.5/31]? Uncertainty in FWHM
80- 84 F5.1 K.km/s Int [0.3/101]? Integrated flux
86- 88 F3.1 K.km/s e_Int [0.1/7]? Uncertainty in Int
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Line Line identifier
5 A1 --- l_R1 Limit flag on R1 (1)
7- 10 F4.1 --- R1 [0.8/43]? Ratio of 12CO(2-1) to 13CO(2-1)
12- 14 F3.1 --- e_R1 [0.3/5]? R1 uncertainty
16 A1 --- l_R2 Limit flag on R2 (1)
18- 22 F5.1 --- R2 [2/144.1]? Ratio of 12CO(2-1) to C18O(2-1)
24- 27 F4.1 --- e_R2 [1/62]? R2 uncertainty
29 A1 --- l_R3 Limit flag on R3 (1)
31- 33 F3.1 --- R3 [0.1/5.1]? Ratio of 13CO(2-1) to 13CO(1-0)
35- 37 F3.1 --- e_R3 [0.2/0.4]? R3 uncertainty
39 A1 --- l_R4 Limit flag on R4 (1)
41- 43 F3.1 --- R4 [0.5/9.8]? Ratio of C18O(2-1) to C18O(1-0)
45 A1 --- l_R5 Limit flag on R5 (1)
47- 50 F4.1 --- R5 [0.3/22]? Ratio of 13CO(2-1) to C18O(2-1)
52- 55 F4.1 --- e_R5 [0.6/12.1]? R5 uncertainty
57 A1 --- l_R6 Limit flag on R6 (1)
59- 61 F3.1 --- R6 [0.1/8.4]? Ratio of 13CO(1-0) to HCN(1-0)
63- 65 F3.1 --- e_R6 [0.8/3]? R6 uncertainty
67 A1 --- l_R7 Limit flag on R7 (1)
69- 71 F3.1 --- R7 [0.5/0.8]? Ratio of HCN(1-0) to HCO+(1-0)
73- 75 F3.1 --- e_R7 [0.1/0.3]? R7 uncertainty
77 A1 --- l_R8 Limit flag on R8 (1)
79- 81 F3.1 --- R8 [1.4/3.5]? Ratio of HCN(1-0) to HNC(1-0)
83- 85 F3.1 --- e_R8 [0.3/0.9]? R8 uncertainty
87 A1 --- l_R9 Limit flag on R9 (1)
89- 91 F3.1 --- R9 [1.7/4.3]? Ratio of HCN(1-0) to CN(1-0)
93- 95 F3.1 --- e_R9 [0.2/1.3]? R9 uncertainty
97 A1 --- l_R10 Limit flag on R10 (1)
99-101 F3.1 --- R10 [1.3/7]? Ratio of HCN(1-0) to CCH(1-0)
103-105 F3.1 --- e_R10 [0.7/1]? R10 uncertainty
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Note (1): Limits are given for values where only a single transition was
detected.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Jul-2018