J/A+A/586/A50 Central Molecular Zone H2CO temperature maps (Ginsburg+, 2016)
Dense gas in the Galactic central molecular zone is warm and heated
by turbulence.
Ginsburg A., Henkel C., Ao Y., Riquelme D., Kauffmann J., Pillai T.,
Mills E.A.C., Requena-Torres M.A., Immer K., Testi L., Ott J., Bally J.,
Battersby C., Darling J., Aalto S., Stanke T., Kendrew S.,
Kruijssen J.M.D., Longmore S., Dale J., Guesten R., Menten K.M.
<Astron. Astrophys. 586, A50 (2016)>
=2016A&A...586A..50G 2016A&A...586A..50G (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Molecular clouds
Keywords: Galaxy: center - ISM: molecules - ISM: structure - Galaxy: nucleus -
cosmic rays - ISM: clouds
Abstract:
The Galactic center is the closest region in which we can study star
formation under extreme physical conditions like those in
high-redshift galaxies.
We measure the temperature of the dense gas in the Central Molecular
Zone (CMZ) and examine what drives it.
We have mapped the inner 300pc of the CMZ in the
temperature-sensitive J=3-2 para-formaldehyde (p-H2CO) transitions.
We use the 32,1-22,0/30,3-20,2 line ratio to determine the gas
temperature in n∼104-105cm-3 gas. We produce temperature maps
and cubes with 30" and 1km/s resolution and publish all data in FITS
form; they can be recovered from digital object identifier
doi:10.7910/DVN/27601.
Description:
We observed the Central Molecular Zone from -0.4°<l<1.6° with
the APEX-1 (SHFI) instrument on the Atacama Pathfinder Experiment
(APEX) telescope using the eXtended bandwidth Fast Fourier Transform
Spectrometer (XFFTS) backend. The observations were performed in
service mode and were spread out over two years. The time was divided
into 25 hours in June 2013, 75 hours in April-July 2014, and 50 hours
in October 2014. A final set of observations was taken in April 2015;
these data are not included in the analysis in this paper but are
provided in the delivered FITS files. The time was split between the
ESO (E-093.C- 0144A; 50h, E-095.C-0242A, 25h), MPIfR (M-091.F-0019 and
M-093.F-0009; 75h), and OSO (E-093.C-0144A; 25h) queues.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fitted.dat 795 204 Fitted line parameters Chi2 constraints
temp.dat 946 352 PPV H2CO temperature
list.dat 283 36 list of fits files
cubes/* . 9 Individual data cubes
integrated/* . 27 Individual integrated files
hdf5/* . . DendroMask_H2CO303202.hdf5 file
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Byte-by-byte Description of file: fitted.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- Name Source name in the accompanying .reg files
21 I1 --- m_Name [0/2] Component number for the source
(there may be multiple velocity components
per source)
23- 35 F13.9 deg GLON Galactic longitude
37- 49 F13.10 deg GLAT Galactic latitude
51- 65 F15.12 K aH2CO Fitted H2CO 303 amplitude (TA*)
67- 82 F16.14 K e_aH2CO Error on ampH2CO
84- 98 F15.13 --- r303321 Fitted 303/321 ratio (h2coratio321303)
100-115 F16.14 --- e_r303321 Error on r303/321 (e_h2coratio321303)
117-132 F16.12 km/s center Velocity centroid (LSR)
134-148 F15.13 km/s e_center Error on center
150-163 F14.11 km/s width Velocity width (sigma)
165-179 F15.13 km/s e_width Error on width
181-194 F14.12 --- r321322 Fitted 321/322 ratio (h2coratio322321)
196-211 F16.14 --- e_r321322 Error on r321/322 (e_h2coratio322321)
213-228 F16.14 K aCH3OH Fitted CH3OH amplitude (TA*)
230-245 F16.14 K e_aCH3OH Error on ampCH3OH
247-262 E16.14 K spaCH3OH Spline-baselined spectra:
Fitted H2CO 303 amplitude (TA*)
(spline_ampCH3OH)
264-279 F16.14 K e_spaCH3OH Spline-baselined spectra:
Error on ampH2CO (esplineampCH3OH)
281-296 F16.12 km/s spcenter Spline-baselined spectra:
velocity centroid (LSR)(spline_center)
298-312 F15.13 km/s e_spcenter Spline-baselined spectra:
Error on spcenter (esplinecenter)
314-328 F15.13 --- spr303321 Spline-baselined spectra: Fitted
303/321 ratio(spline_h2coratio321303)
330-345 F16.14 --- e_spr303321 Spline-baselined spectra: Error on
spr303321 (esplineh2coratio321303)
347-360 F14.11 km/s spwidth Spline-baselined spectra:
Velocity width (sigma) (spline_width)
362-376 F15.13 km/s e_spwidth Spline-baselined spectra:
Error on spwidth (esplinewidth)
378-391 F14.12 --- spr321322 Spline-baselined spectra: Fitted
321/322 ratio (spline_h2coratio322321)
393-408 F16.14 --- e_spr321322 Spline-baselined spectra: Error on
spr321322 (esplineh2coratio322321)
410-425 F16.13 K spaH2CO Spline-baselined spectra: Fitted CH3OH
amplitude (TA*) (spline_ampH2CO)
427-442 F16.14 K e_spaH2CO Spline-baselined spectra:
Error on aCH3OH (esplineampH2CO)
444-458 F15.13 deg Boxwidth Width of the box region (deg)
460-474 F15.13 deg Boxheight Height of the box region (deg)
476-491 F16.14 deg Radius Radius of the circular region
493-509 F17.15 deg+2 Area Region area
511-522 F12.8 deg PA Position angle of the box region (posang)
524 I1 --- is_good [0/1] Are the line fits good enough
to use in plotting?
526-542 E17.12 cm-2 NHI Herschel Hi-Gal derived mean column
density (higalcolumndens)
544-556 F13.10 K HITd Herschel Hi-Gal derived mean
temperature (higaldusttem)
558-571 F14.10 K TgX2 Chi2 fitting derived gas temperature
(temperature_chi2)
573-586 F14.10 K e_TgX2 ?=- Chi2 1-sigma lower limit on
temperature (tmin1sig_chi2)
588-601 F14.10 K E_TgX2 ?=- Chi2 1-sigma upper limit on
temperature (tmax1sig_chi2)
603-616 F14.10 cm-2 NH2COX2 ?=- Chi2 fitting derived H2CO column
density (column_chi2)
618-630 F13.10 cm-2 e_NH2COX2 Chi2 1-sigma lower limit on H2CO
column density (cmin1sig_chi2)
632-644 F13.10 cm-2 E_NH2COX2 ? Chi2 1-sigma upper limit on H2CO
column density (cmax1sig_chi2)
646-658 F13.10 cm-3 dgX2 ? Chi2 fitting derived gas density
(density_chi2)
660-672 F13.10 cm-3 e_dgX2 ? Chi2 1-sigma lower limit on gas
density (dmin1sig_chi2)
674-686 F13.11 cm-3 E_dgX2 Chi2 1-sigma upper limit on gas
density (dmax1sig_chi2)
688-700 F13.11 [cm-2] logNH2 ? Log of the Herschel hi-gal column
density (logh2column)
702-714 F13.11 [cm-2] e_logNH2 ? Error on logh2column
716-728 F13.11 [-] logAbd ? Log abundance of H2CO relative to H2
(logabundance)
730-742 F13.10 [-] e_logAbd Error on logAbd
744-746 F3.1 K Tkin Predicted kinetic temperature of the
gas from turbulent heating (tkin_turb)
748-761 F14.11 pc reff Effective radius of the region (reff_pc)
763-765 F3.1 K Texp Expectation value of the derived gas
temperature (expected_temperature)
767-780 F14.10 cm-2 Nexp Expectation value of the derived H2CO
column density (expected_column)
782-795 F14.11 cm-2 dexp Expectation value of the derived H2
volume density (expected_density)
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Byte-by-byte Description of file: temp.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Name [0/351] ID number of the dendrogram source
5- 10 I6 --- npix Number of voxels included in the source
12- 27 F16.9 arcsec+2 AreaEll Area of the fitted ellipse (area_ellipse)
29- 37 F9.2 arcsec+2 Area Summed area of the pixels included in
the source (projected) (area_exact)
39- 54 F16.10 K Flux Sum of the brightness in the source voxels
56- 70 F15.11 arcsec maj Major axis of the fitted ellipse
(major_sigma)
72- 86 F15.11 arcsec min Minor axis of the fitted ellipse
(minor_sigma)
88-102 F15.10 deg PA [] Position angle of the fitted ellipse
(position_angle)
104-119 F16.11 arcsec radius Effective radius (in arcsec)
121-134 F14.12 pc reff Effective radius (in pc)
136-154 F19.14 km/s vcen Velocity centroid
156-169 F14.11 km/s vrms Velocity RMS
171-188 F18.14 deg xcen Galactic Longitude centroid (x_cen)
190-206 E17.15 deg ycen Galactic Latitude centroid (y_cen)
208-224 F17.14 deg GLON [] Galactic Longitude centroid
226-242 E17.15 deg GLAT Galactic Latitude centroid
244 A1 --- is_leaf [T/F] Is the source a "Leaf" in
the dendrogram?
246-248 I3 --- parent Index of the parent structure
(-1 indicates it is a root)
250-252 I3 --- root Index of the root structure
(root≡index if it is a root)
254-271 F18.12 K Stot321 Total brightness in the 321 line
273-289 F17.14 K Smean321 Mean brightness in the 321 line
291-307 F17.15 K e321 Noise estimate for the 321 line
309-324 F16.10 K Stot303 Total brightness in the 303 line
326-339 F14.12 K Smean303 Mean brightness in the 303 line
341-357 F17.15 K e303 Noise estimate for the 303 line
359-374 F16.9 --- sntotal Sum of the signal-to-noise cube over the
extracted source (s_ntotal)
376-391 F16.14 --- r303321 Ratio of the 303/321 lines
393-409 F17.15 --- e_r303321 Error on the ratio of the 303/321 lines
411-427 F17.10 K 13COsum Sum of the 13CO brightness
429-444 F16.13 K 13COmean Mean of the 13CO brightness
446-462 F17.11 K C18Osum Sum of the C18O brightness
464-479 F16.13 K C18Omean Mean of the C18O brightness
481-494 F14.11 [-] logAbd Assumed log abundance (logabundance)
496-498 F3.1 [-] e_logAbd Error on the assumed log abundance
(e_elogabundance)
500-512 F13.10 [cm-2] logNH2 HiGal column density (logh2column)
514-516 F3.1 [cm-2] e_logNH2 Error on the HiGal column density
(e_logh2column)
518-524 F7.4 K HITd HiGal mean dust temperature (higaldusttem)
526-541 F16.9 Msun HIMass HiGal dust-derived gas mass (dustmass)
543-558 F16.8 cm-3 dg HiGal dust-derived gas density (dustmindens)
560-572 F13.11 cm-3 ddX2 Chi2fitted dust density (density_chi2)
574-586 F13.11 cm-3 ddX2m 1-sigma minimum Chi2 fitted dust density
(dmin1sig_chi2)
588-600 F13.11 cm-3 ddX2M 1-sigma maximum Chi2 fitted dust density
(dmax1sig_chi2)
602-618 F17.14 cm-3 e_ddX2 lower 1-sigma error bar on Chi2 fitted dust
density (elo_d)
620-633 F14.12 cm-3 E_ddX2 upper 1-sigma error bar on Chi2 fitted dust
density (ehi_d)
635-648 F14.10 K TdX2 Chi2fitted temperature (temperature_chi2)
650-663 F14.10 K TdX2m 1-sigma minimum Chi2fitted temperature
(tmin1sig_chi2)
665-678 F14.10 K TdX2M 1-sigma maximum Chi2fitted temperature
(tmax1sig_chi2)
680-694 F15.11 K e_TdX2 lower 1-sigma error bar on Chi^2 fitted
temperature (elo_t)
696-711 F16.12 K E_TdX2 upper 1-sigma error bar on Chi^2 fitted
temperature (ehi_t)
713-725 F13.10 cm-2 NH2COX2 Chi2fitted H2CO column per km/s per pc
(column_chi2)
727-739 F13.10 cm-2 NH2COX2m 1-sigma minimum Chi2fitted H2CO column per
km/s per pc (cmin1sig_chi2)
741-753 F13.10 cm-2 NH2COX2M 1-sigma maximum Chi2fitted H2CO column per
km/s per pc (cmax1sig_chi2)
755-769 F15.13 cm-2 e_NH2COX2 lower 1-sigma error bar on Chi2 fitted H2CO
column per km/s per pc (elo_c)
771-786 F16.13 cm-2 E_NH2COX2 upper 1-sigma error bar on Chi2 fitted H2CO
column per km/s per pc (ehi_c)
788 A1 --- bad [F/T] Flag indicating the source is probably
bad (usually HC3N)
790 A1 --- NotH2CO [F/T] Flag indicating the source is HC3N
792 A1 --- IsAbs [F/T] Flag indicating the source is
associated with absorption in Sgr B2
(IsAbsorption)
794-807 F14.10 K Texp Expectation value of the derived gas
temperature (expected_temperature)
809-821 F13.10 cm-2 Nexp Expectation value of the derived H2CO column
(expected_column)
823-835 F13.11 cm-3 dexp Expectation value of the
derived H2 volume density (expected_density)
837-850 F14.10 K DespTem DESPOTIC-predicted temperature from turbulent
decay heat (DespoticTem)
852-864 F13.11 --- Gausscf Gaussian correction factor for extracted
sources (gausscorrfactor)
866-879 F14.12 K Smin303 Minimum brightness temperature within the
source
881-894 F14.12 K Smax303 Maximum brightness temperature within the
source
896-911 F16.13 Myr OrbitTime Time along the Kruijssen et al. 2015 orbit
since the Brick's pericenter approach
(OrbitTime)
913-928 F16.12 km/s ModelVel Velocity predicted by the Kruijssen model
(ModelVelo)
930-946 F17.15 pc pDist Projected distance from the nearest point
along the Kruijssen model (DistanceFromOrbit)
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1 A1 --- --- [G]
2- 10 F9.5 deg GLON ? Galactic longitude
11- 19 F9.5 deg GLAT ? Galactic latitude
21- 23 F3.1 arcsec/pix Scale ? Scale
25- 28 I4 --- Nx Number of pixels along X-axis
30- 32 I3 --- Ny Number of pixels along Y-axis
34- 37 I4 --- Nz ? Nuber of slices for data cubes
39- 42 I4 km/s b_Vrad ? Lower value of radial velocity interval
44- 46 I3 km/s B_Vrad ? Upper value of radial velocity interval
48 I1 km/s dVrad ? Radial velocity resolution
50- 57 E8.3 Hz b_Freq ? Lower value of frequency interval
59- 69 E11.3 Hz B_Freq ? Upper value of frequency interval
71- 76 I6 Hz dFreq ? Frequency resolution
78- 84 I7 Kibyte Size Size of the fits file
86-186 A101 --- Title Title of the file
188-283 A96 --- FileName Name of the fits datacube
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Acknowledgements:
Adam Ginsburg, adam.g.ginsburg(at)gmail.com
(End) Patricia Vannier [CDS] 21-Aug-2015