Ammonia (<i>J,K</i>)=(1,1) to (4,4) and (6,6) inversion lines detected in the Seyfert 2 galaxy NGC 1068

Ao, Yiping; Henkel, C.; Braatz, J. A.; Weiß, A.; Menten, K. M.; Mühle, S.

doi:10.1051/0004-6361/201116595

Cited by 18 publications

(19 citation statements)

References 28 publications

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“…The dust emission at mid-infrared (MIR) emission traces primarily warm dust components (Helou 1986). Dust temperatures derived from MIR multi-filter data agree with gas temperatures derived from multi-inversion transitions of NH 3 in external galaxies (Melo et al 2002;Tomono et al 2006;Ao et al 2011;Mauersberger et al 2003). Combining the MIR data for our sample, the fit of the warm gas emission in the SED shows a cold and a warm component (see König et al 2017).…”

Section: Comparison Of Kinetic Temperatures Derived From Gas and Dustsupporting

confidence: 75%

ATLASGAL-selected massive clumps in the inner Galaxy

Tang

Henkel

Wyrowski

et al. 2018

A&A

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Context. Formaldehyde (H 2 CO) is a reliable tracer to accurately measure the physical parameters of dense gas in star-forming regions. Aims. We aim to determine directly the kinetic temperature and spatial density with formaldehyde for the ∼100 brightest ATLASGALselected clumps (the TOP100 sample) at 870 µm representing various evolutionary stages of high-mass star formation. Methods. Ten transitions (J = 3-2 and 4-3) of ortho-and para-H 2 CO near 211, 218, 225, and 291 GHz were observed with the Atacama Pathfinder EXperiment (APEX) 12 m telescope. Results. Using non-LTE models with RADEX, we derived the gas kinetic temperature and spatial density with the measured para-H 2 CO 3 21 -2 20 /3 03 -2 02 , 4 22 -3 21 /4 04 -3 03 , and 4 04 -3 03 /3 03 -2 02 ratios. The gas kinetic temperatures derived from the para-H 2 CO 3 21 -2 20 /3 03 -2 02 and 4 22 -3 21 /4 04 -3 03 line ratios are high, ranging from 43 to >300 K with an unweighted average of 91 ± 4 K. Deduced T kin values from the J = 3-2 and 4-3 transitions are similar. Spatial densities of the gas derived from the para-H 2 CO 4 04 -3 03 /3 03 -2 02 line ratios yield 0.6-8.3 × 10 6 cm −3 with an unweighted average of 1.5 (±0.1) × 10 6 cm −3 . A comparison of kinetic temperatures derived from para-H 2 CO, NH 3 , and dust emission indicates that para-H 2 CO traces a distinctly higher temperature than the NH 3 (2,2)/(1,1) transitions and the dust, tracing heated gas more directly associated with the star formation process. The H 2 CO line widths are found to be correlated with bolometric luminosity and increase with the evolutionary stage of the clumps, which suggests that higher luminosities tend to be associated with a more turbulent molecular medium. It seems that the spatial densities measured with H 2 CO do not vary significantly with the evolutionary stage of the clumps. However, averaged gas kinetic temperatures derived from H 2 CO increase with time through the evolution of the clumps. The high temperature of the gas traced by H 2 CO may be mainly caused by radiation from embedded young massive stars and the interaction of outflows with the ambient medium. For L bol /M clump 10 L ⊙ /M ⊙ , we find a rough correlation between gas kinetic temperature and this ratio, which is indicative of the evolutionary stage of the individual clumps. The strong relationship between H 2 CO line luminosities and clump masses is apparently linear during the late evolutionary stages of the clumps, indicating that L H 2 CO does reliably trace the mass of warm dense molecular gas. In our massive clumps H 2 CO line luminosities are approximately linearly correlated with bolometric luminosities over about four orders of magnitude in L bol , which suggests that the mass of dense molecular gas traced by the H 2 CO line luminosity is well correlated with star formation.

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Section: Comparison Of Kinetic Temperatures Derived From Gas and Dustsupporting

confidence: 75%

ATLASGAL-selected massive clumps in the inner Galaxy

Tang

Henkel

Wyrowski

et al. 2018

A&A

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“…1. The intensity of the (3, 3) ortho line is stronger than that of the (2, 2) para line as often seen in other sources (e.g., in NGC 253 and NGC 1068, Takano et al 2002;Mauersberger et al 2003;Ao et al 2011). The width of each line (FWHM) is about 120 km s −1 .…”

Section: Resultsmentioning

confidence: 54%

“…In addition, the spatial distributions of ammonia in IC 342 were mapped with the VLA by Ho & Martin (1983) and Ho et al (1990). Ammonia was also observed in the Large Magellanic Cloud (LMC; Ott et al 2010), other nearby galaxies Cen A, Maffei2, M 82, and NGC 1068 (Seaquist & Bell 1990;Henkel et al 2000;Takano et al 2000Takano et al , 2002Weiß et al 2001;Ao et al 2011), Arp 220 (Takano et al 2005;Ott et al 2005Ott et al , 2011, and more distant sources B0218+357 ) and PKS1830-211 (Henkel et al 2008). These data indicate large variations in ammonia abundance among galaxies that are not yet well understood.…”

Section: Introductionmentioning

confidence: 99%

Detection of ammonia in M 51

Takano

Nakai

et al. 2013

A&A

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Aims. To study the abundance and temperature of ammonia in the center of a nearby galaxy M 51 and to compare them with those in other nearby galaxies, we observed its (J, K) = (1, 1), (2, 2), (3, 3), and (4, 4) inversion transitions at the wavelength of 1.3 cm. Methods. The observations were carried out with the Effelsberg 100-m radio telescope. Results. The (1, 1), (2, 2), and (3, 3) transitions are clearly detected, but the (4, 4) transition is barely detected. The rotational temperature obtained from the (1, 1) and (2, 2) transitions of para-ammonia is 25 ± 2 K, which is similar to those of M 82 and the Large Magellanic Cloud (N 159 W), but significantly lower than those of IC 342 and NGC 1068 among the nearby galaxies. The column density of ammonia is (8.1 ± 2.4) × 10 13 cm −2 , and the abundance relative to H 2 is ∼4.5 × 10 −9 . The abundance in M 51 is about a factor of 5 lower than those of NGC 253 and IC 342, but about one order of magnitude higher than those of M 82 and the Large Magellanic Cloud. The addition of the data of M 51 further supports the exceptionally low abundances of ammonia reported previously in these two galaxies. For understanding the abundance of ammonia in M 51 and other nearby galaxies, their temperatures were compared. As a result, we found that the galaxies with low temperature tend to have low abundance of ammonia. In addition, the photodissociation rate of ammonia was compared to those of related molecules detected in the nearby galaxies to discuss the effect of photodissociation. We found that the low abundance of ammonia in some galaxies cannot be explained only by the effect of photodissociation.

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“…Kinetic temperatures of starburst galaxies measured with multiinversion transitions of NH 3 show a range from 24 to 250 K (Henkel et al 2000Mauersberger et al 2003;Ao et al 2011;Lebrón et al 2011;Mangum et al 2013a). The temperatures derived from para-H 2 CO line ratios in the LMC overlap with the values found for a sample at lower temperature (e.g., M83, NGC6946).…”

Section: Comparison Of Temperatures Derived From H 2 Co Co Nh 3 Amentioning

confidence: 99%

“…Multi-level observations of suitable molecules deliver the most reliable temperature determinations. The metastable lines of ammonia (NH 3 ) are frequently used as the standard molecular cloud thermometer in molecular clouds within our Galaxy and also in external galaxies (Ho & Townes 1983;Walmsley & Ungerechts 1983;Danby et al 1988;Henkel et al 2000Henkel et al , 2008Weiß et al 2001;Mauersberger et al 2003;Ao et al 2011;Lebrón et al 2011;Ott et al 2011;Wienen et al 2012;Mangum et al 2013a). However, the ammonia abundance can vary strongly in different molecular environments (e.g., 10…”

Section: Introductionmentioning

confidence: 99%

Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde

Tang

Henkel

Chen

et al. 2017

A&A

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Context. The kinetic temperature of molecular clouds is a fundamental physical parameter affecting star formation and the initial mass function. The Large Magellanic Cloud (LMC), the closest star forming galaxy with low metallicity, provides an ideal laboratory to study star formation in such an environment. Aims. The classical dense molecular gas thermometer NH 3 is rarely available in a low metallicity environment because of photoionization and a lack of nitrogen atoms. Our goal is to directly measure the gas kinetic temperature with formaldehyde toward six star-forming regions in the LMC. Methods. Three rotational transitions (J K A K C = 3 03 -2 02 , 3 22 -2 21 , and 3 21 -2 20 ) of para-H 2 CO near 218 GHz were observed with the Atacama Pathfinder EXperiment (APEX) 12 m telescope toward six star forming regions in the LMC. Those data are complemented by C 18 O 2-1 spectra. Results. Using non-LTE modeling with RADEX, we derive the gas kinetic temperature and spatial density, using as constraints the measured para-H 2 CO 3 21 -2 20 /3 03 -2 02 and para-H 2 CO 3 03 -2 02 /C 18 O 2-1 ratios. Excluding the quiescent cloud N159S, where only one para-H 2 CO line could be detected, the gas kinetic temperatures derived from the preferred para-H 2 CO 3 21 -2 20 /3 03 -2 02 line ratios range from 35 to 63 K with an average of 47 ± 5 K (errors are unweighted standard deviations of the mean). Spatial densities of the gas derived from the para-H 2 CO 3 03 -2 02 /C 18 O 2-1 line ratios yield 0.4 -2.9 × 10 5 cm −3 with an average of 1.5 ± 0.4 × 10 5 cm −3 . Temperatures derived from the para-H 2 CO line ratio are similar to those obtained with the same method from Galactic star forming regions and agree with results derived from CO in the dense regions (n(H 2 ) > 10 3 cm −3 ) of the LMC. A comparison of kinetic temperatures derived from para-H 2 CO with those from the dust also shows good agreement. This suggests that the dust and para-H 2 CO are well mixed in the studied star forming regions. A comparison of kinetic temperatures derived from para-H 2 CO 3 21 -2 20 /3 03 -2 02 and NH 3 (2,2)/(1,1) shows, however, a drastic difference. In the star forming region N159W, the gas temperature derived from the NH 3 (2,2)/(1,1) line ratio is ∼16 K (Ott et al. 2010), which is only half the temperature derived from para-H 2 CO and the dust. Furthermore, ammonia shows a very low abundance in a 30 ′′ beam. Apparently, ammonia only survives in the most shielded pockets of dense gas not yet irradiated by UV photons, while formaldehyde, less affected by photodissociation, is more widespread and is also sampling regions more exposed to the radiation of young massive stars. A correlation between the gas kinetic temperatures derived from para-H 2 CO and infrared luminosity, represented by the 250 µm flux, suggests that the kinetic temperatures traced by para-H 2 CO are correlated with the ongoing massive star formation in the LMC.

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Ammonia (J,K)=(1,1) to (4,4) and (6,6) inversion lines detected in the Seyfert 2 galaxy NGC 1068

Cited by 18 publications

References 28 publications

ATLASGAL-selected massive clumps in the inner Galaxy

ATLASGAL-selected massive clumps in the inner Galaxy

Detection of ammonia in M 51

Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde

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