A<i>λ</i>= 1.3 mm and 2 mm molecular line survey towards M 82

Aladro, R.; Martín, S.; Martı́n-Pintado, J.; Mauersberger, R.; Henkel, C.; Flaquer, B. Ocaña; Amo-Baladrón, M. A.

doi:10.1051/0004-6361/201117397

Cited by 86 publications

(140 citation statements)

References 120 publications

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“…Millimeter/submillimeter (mm/submm) spectroscopic diagnostics are particularly important because intense starbursts are often deeply dust-enshrouded, especially in their early phase where limited information is available at other wavelengths. Previous mm/submm spectral scans of local starburst galaxies (e.g., Martín et al 2006;Aladro et al 2011;Martín et al 2011;Costagliola et al 2015) have demonstrated the richness of the molecular emission lines. Spatially resolved spectral line surveys are performed toward a limited number of representative galaxies such as NGC 253 (Meier et al 2015), NGC 1068 (Takano et al 2014;Nakajima et al 2015), NGC 1097 (Martín et al 2015), IC 342 (Meier & Turner 2005), and Maffei 2 (Meier & Turner 2012).…”

Section: Introductionmentioning

confidence: 99%

Diverse Nuclear Star-forming Activities in the Heart of NGC 253 Resolved with 10-pc-scale ALMA Images

Ando

Nakanishi

Kohno

et al. 2017

ApJ

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We present an 8 pc × 5 pc resolution view of the central ∼ 200 pc region of the nearby starburst galaxy NGC 253, based on ALMA Band 7 (λ 0.85 mm or ν ∼ 350 GHz) observations covering 11 GHz. We resolve the nuclear starburst of NGC 253 into eight dusty star-forming clumps, 10 pc in scale, for the first time. These clumps, each of which contains (4-10) ×10 4 M of dust (assuming that the dust temperature is 25 K) and up to 6 × 10 2 massive (O5V) stars, appear to be aligned in two parallel ridges, while they have been blended in previous studies. Despite the similarities in sizes and dust masses of these clumps, their line spectra vary drastically from clump to clump although they are separated by only ∼ 10 pc. Specifically, one of the clumps, Clump 1, exhibits line confusion-limited spectra with at least 36 emission lines from 19 molecules (including CH 3 OH, HNCO, H 2 CO, CH 3 CCH, H 2 CS, and H 3 O + ) and a hydrogen recombination line (H26α), while much fewer kinds of molecular 3 lines are detected in some other clumps where fragile species, such as complex organic molecules and HNCO, completely disappear from their spectra. We demonstrate the existence of hot molecular gas (T rot (SO 2 ) = 90 ± 11 K) in the former clump, which suggests that the hot and chemically rich environments are localized within a 10-pc scale star-forming clump.

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Section: Introductionmentioning

confidence: 99%

Diverse Nuclear Star-forming Activities in the Heart of NGC 253 Resolved with 10-pc-scale ALMA Images

Ando

Nakanishi

Kohno

et al. 2017

ApJ

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“…Most of the deep and/or unbiased chemical studies in galaxies have been carried out at very low resolution (i.e., 100 pc, Wang et al 2004;Martín et al 2006Martín et al , 2011Aladro et al 2011aAladro et al , 2013Davis et al 2013;Watanabe et al 2014) but for absorption studies toward bright continuum high-z sources where, though extremely prolific in molecular detection, no spatial information can be obtained (Muller et al 2011(Muller et al , 2014. High resolution studies toward extragalactic sources have mostly focused toward the brightest nearby galaxies, as well as on the brightest species after carbon monoxide: HCN and HCO + (NGC 253 at 3 resolution, Knudsen et al (2007); M51 at 4 , Schinnerer et al 2010; NGC 1068 at 1 , Krips et al 2011; NGC 1097 at 3 , Hsieh et al 2012; or a sample of luminous infrarred galaxies (LIRGs) at 2 −10 , Imanishi et al 2007Imanishi et al , 2009).…”

Section: Introductionmentioning

confidence: 99%

Multimolecule ALMA observations toward the Seyfert 1 galaxy NGC 1097

Martín

Kohno

Izumi

et al. 2015

A&A

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Context. The nearby Sy 1 galaxy NGC 1097 represents an ideal laboratory for exploring the molecular chemistry in the surroundings of an active galactic nucleus (AGN). Aims. Exploring the distribution of different molecular species allows us to understand the physical processes affecting the interstellar medium both in the AGN vicinity and in the outer star forming molecular ring. Methods. We carried out 3 mm ALMA observations that include seven different molecular species, namely HCN, HCO + , CCH, CS, HNCO, SiO, HC 3 N, and SO, as well as the 13 C isotopologues of the first two. Spectra were extracted from selected positions and all species were imaged over the central 2 kpc (∼30 ) of the galaxy at a resolution of ∼2.2 × 1.5 (150 pc × 100 pc). Results. HCO + and CS appear to be slightly enhanced in the star forming ring. CCH shows the largest variations across NGC 1097 and is suggested to be a good tracer of both obscured and early stage star formation. HNCO, SiO, and HC 3 N are significantly enhanced in the inner circumnuclear disk surrounding the AGN. Conclusions. Differences in the molecular abundances are observed between the star forming ring and the inner circumnuclear disk. We conclude that the HCN/HCO + and HCN/CS differences observed between AGN-dominated and starburst (SB) galaxies are not due to a HCN enhancement due to X-rays, but rather this enhancement is produced by shocked material at distances of 200 pc from the AGN. Additionally, we claim that lower HCN/CS is a combination of a small underabundance of CS in AGNs, together with excitation effects, where a high density gas component (∼10 6 cm −3 ) may be more prominent in SB galaxies. However, the most promising are the differences found among the dense gas tracers that, at our modest spatial resolution, seem to outline the physical structure of the molecular disk around the AGN. In this picture, HNCO probes the well-shielded gas in the disk, surrounding the dense material moderately exposed to the X-ray radiation traced by HC 3 N. Finally SiO might be the innermost molecule in the disk structure.

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“…Yun et al (1994) and Chynoweth et al (2008) found a large amount of H  filling the whole group as well as three distinct spurs, which connect the main galaxies of the group: M 81, M 82, and NGC 3077. Additionally, M 82 is well known for its large fraction of molecular gas in the central region (Aladro et al 2011;Naylor et al 2010). Observations by Greaves et al (2000) show a giant magnetic molecular bubble that was possibly blown out by the superwind.…”

Section: Introductionmentioning

confidence: 99%

M 82 – A radio continuum and polarisation study

Adebahr

Krause

Klein

et al. 2013

A&A

104

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Context. The potential role of magnetic fields and cosmic ray propagation for feedback processes in the early Universe can be probed by studies of local starburst counterparts with an equivalent star-formation rate. Aims. In order to study the cosmic ray propagation and determine the magnetic field strength and dominant loss processes in the nearby prototypical starbursting galaxy M 82, a multi-frequency analysis at four radio wavelengths is presented. Methods. Archival data from the Westerbork Synthesis Radio Telescope (WSRT) was reduced and a new calibration technique introduced to reach the high dynamic ranges needed for the complex source morphology. These data were combined with archival Very Large Array (VLA) data, yielding total power maps at λ3 cm, λ6 cm, λ22 cm, and λ92 cm. Results. The data show a confinement of the emission at wavelengths of λ3/λ6 cm to the core region and a largely extended halo reaching up to 4 kpc away from the galaxy midplane at wavelengths of λ22/λ92 cm up to a sensitivity limit of 90 µJy and 1.8 mJy respectively indicating different physical processes in the core and halo regions. The results are used to calculate the magnetic field strength to 98 µG in the core region and to 24 µG in the halo regions. From the observation of ionisation losses, the filling factor of the ionised medium could be estimated to 2%. This leads to a revised view of the magnetic field distribution in the core region and the propagation processes from the core into the halo regions. Conclusions. We find that the radio emission from the core region is dominated by very dense H -regions and supernova remnants, while the surrounding medium is filled with hot X-ray and neutral gas. Cosmic rays radiating at frequencies higher than 1.4 GHz suffer from high synchrotron and inverse Compton losses in the core region and are not able to reach the halo. Even the cosmic rays radiating at longer wavelengths are only able to build up the observed kpc-sized halo, when several starbursting periods are assumed where the far-infrared and radio luminosity vary by an order of magnitude. These findings, together with the strong correlation between Hα, ionised polycyclic aromatic hydrocarbons (PAH + ), and our radio continuum data, suggest a magnetic field which is frozen into the ionised medium and driven out of the galaxy kinematically.

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Aλ= 1.3 mm and 2 mm molecular line survey towards M 82

Cited by 86 publications

References 120 publications

Diverse Nuclear Star-forming Activities in the Heart of NGC 253 Resolved with 10-pc-scale ALMA Images

Diverse Nuclear Star-forming Activities in the Heart of NGC 253 Resolved with 10-pc-scale ALMA Images

Multimolecule ALMA observations toward the Seyfert 1 galaxy NGC 1097

M 82 – A radio continuum and polarisation study

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