Star bursts and the extraordinary galaxy NGC 3690

Gehrz, R. D.; Sramek, R. A.; Weedman, D. W.

doi:10.1086/160892

Cited by 103 publications

(158 citation statements)

References 0 publications

Supporting

Mentioning

152

Contrasting

Unclassified

Order By: Relevance

“…They further concluded that the excitation in Arp 299B and Arp 299C is consistent with heating from ultraviolet photons in photon-dominated regions (PDRs) while the excitation in Arp 299A requires an additional heating mechanism with mechanical heating being the most likely. Based on optical, radio, and IR data, Gehrz et al (1983) found that the emission from Arp 299, except for the radio source in Arp 299A, is consistent with starbursts at different locations. A compact condensation of molecular gas in the nucleus of Arp 299A was suggested by Sargent & Scoville (1991) to harbor an AGN.…”

Section: Introductionmentioning

confidence: 94%

See 1 more Smart Citation

Inflowing gas onto a compact obscured nucleus in Arp 299A

Falstad¹,

González-Alfonso²,

Aalto³

et al. 2017

A&A

View full text Add to dashboard Cite

Aims. We probe the physical conditions in the core of Arp 299A and try to put constraints to the nature of its nuclear power source. − doublet at 119 µm is found redshifted by ∼175 km s −1 compared with other OH and H 2 O lines, suggesting a low excitation inflow. We find that at least two components are required in order to account for the excited molecular line spectrum. The inner component has a radius of 20 − 25 pc, a very high infrared surface brightness ( 3 × 10 13 L ⊙ kpc −2 ), warm dust (T d > 90 K), and a large H 2 column density (N H 2 > 10 24 cm −2 ). The modeling also indicates high nuclear H 2 O (1 − 5 × 10 −6 ) and OH (0.5 − 5 × 10 −5 ) abundances relative to H nuclei. The outer component is larger (50 − 100 pc) with slightly cooler dust (70 − 90 K) and molecular abundances that are about one order of magnitude lower. In addition to the two components that account for the excited OH and H 2 O lines, we require a much more extended inflowing component to account for the OH 2 Π 3/2 − 2 Π 3/2 5 2− doublet at 119 µm. Conclusions. The Compton-thick nature of the core makes it difficult to determine the nature of the buried power source, but the high surface brightness indicates that it is either an active galactic nucleus and/or a dense nuclear starburst. Our results are consistent with a composite source. The high OH/H 2 O ratio in the nucleus indicates that ion-neutral chemistry induced by X-rays or cosmic-rays is important. Finally we find a lower limit to the 16 O/ 18 O ratio of 400 in the nuclear region, possibly indicating that the nuclear starburst is in an early evolutionary stage, or that it is fed through a molecular inflow of, at most, solar metallicity.

show abstract

Section: Introductionmentioning

confidence: 94%

“…and Arp 299B) as well as an overlap region (Arp 299C) are strong near-IR and radio emitters due to intense star formation (Gehrz et al 1983;Telesco et al 1985). Based on H i observations, Nordgren et al (1997) determined the systemic velocity of the system to be 3121 km s −1 , yielding a redshift of z = 0.010411.…”

Section: Introductionmentioning

confidence: 99%

Inflowing gas onto a compact obscured nucleus in Arp 299A

Falstad¹,

González-Alfonso²,

Aalto³

et al. 2017

A&A

View full text Add to dashboard Cite

show abstract

“…It is in an early merger stage according to Keel & Wu (1995) or in a mid-stage according to Stierwalt et al (2013) and Larson et al (2016). Arp 299 is formed by two galaxies and exhibits two clear radio nuclei (Gehrz et al 1983), A and B, and two secondary components, C and C . The remaining compact structure, D, is believed to be a background quasar, unrelated to the system (Ulvestad 2009).…”

Section: Arp 299mentioning

confidence: 99%

“…Its different knots show completely different behaviors regarding their radio and near-IR correlation. While the near-IR dominates the emission of the southern nucleus (designated B in the literature Gehrz et al 1983), the northwest component (designated C) has a comparable emission, and the northeast component (C ) is very faint at 2.2 µm. This near-IR faintness was discussed by Alonso-Herrero et al (2000), whose starburst models predict a persistence of the emission at 2 µm after their assumed Gaussian burst with a FWHM of 5 Myr.…”

Section: Radio and Near-ir Comparisonmentioning

confidence: 99%

Star formation and AGN activity in a sample of local luminous infrared galaxies through multiwavelength characterization

Herrero-Illana

Pérez-Torres

Randriamanakoto

et al. 2017

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Nuclear starbursts and AGN activity are the main heating processes in luminous infrared galaxies (LIRGs) and their relationship is fundamental to understand galaxy evolution. In this paper, we study the star-formation and AGN activity of a sample of 11 local LIRGs imaged with subarcsecond angular resolution at radio (8.4 GHz) and near-infrared (2.2 µm) wavelengths. This allows us to characterize the central kpc of these galaxies with a spatial resolution of 100 pc. In general, we find a good spatial correlation between the radio and the near-IR emission, although radio emission tends to be more concentrated in the nuclear regions. Additionally, we use an MCMC code to model their multi-wavelength spectral energy distribution (SED) using template libraries of starburst, AGN and spheroidal/cirrus models, determining the luminosity contribution of each component, and finding that all sources in our sample are starburst-dominated, except for NGC 6926 with an AGN contribution of 64%. Our sources show high star formation rates (40 to 167 M yr −1 ), supernova rates (0.4 to 2.0 SN yr −1 ), and similar starburst ages (13 to 29 Myr), except for the young starburst (9 Myr) in NGC 6926. A comparison of our derived star-forming parameters with estimates obtained from different IR and radio tracers shows an overall consistency among the different star formation tracers. AGN tracers based on mid-IR, high-ionization line ratios also show an overall agreement with our SED model fit estimates for the AGN. Finally, we use our wide-band VLA observations to determine pixel-by-pixel radio spectral indices for all galaxies in our sample, finding a typical median value (α −0.8) for synchrotron-powered LIRGs.

show abstract

“…The contour intervals are 2.3 ] 10~23 W cm~2 arcsec~2 with the H 2 lowest contour level 2.3 ] 10~23 W cm~2 arcsec~2. The designations of components come from Gehrz et al (1983) and Wynn-Williams et al (1991). Two slit positions of grism spectroscopy for Fig.…”

Section: Grism Spectroscopymentioning

confidence: 99%

Near‐Infrared Line Observations of Arp 299 as a Tracer of Activity in the Nuclei

Sugai

Davies

Malkan

et al. 1999

ApJ

View full text Add to dashboard Cite

We have obtained images of the molecular hydrogen and Brc emission lines in the interacting (H 2 ) galaxy system Arp 299. In order to investigate the nuclear activities, we also have obtained H-and K-band spectra for three of its 2 km continuum peaks and also J-band spectra for one of them. From the line ratios of Pac, Pab, Br10, and Brc, and also those between [Fe II] 1.26 km and [Fe II] 1.64 km, we have successfully modeled the extinction for component A as a combination of mag A K \ 2.6 region(s) and mag region(s). The extinction corrected Brc luminosity requires 5 ] 1054 s~1 of A K \ 0.3 Lyman photons, which corresponds to 3 ] 105 "" O6 stars.ÏÏ The mean stellar density within its 100 pc core is comparable to those for the cores in blue compact dwarf galaxies even though the luminosity is almost 2 orders of magnitude larger. The starbursts at the nucleus of component A are probably the most dominant source for the far-infrared emission from this component. In this component, we have found large [Fe II]/H I ratios, which are at the higher end of starburst galaxies and are typical for AGNs or AGN/starburst composites. The nucleus must be in a starburst phase that includes many supernova remnants. The spatial distribution of the emission for this interacting system is similar to that of the H 2 12CO 1È0 emission mapped by Aalto et al. The intensity, however, is not proportional to the CO H 2 intensity among components, because of the di †erence in the excitation mechanism among them. We H 2 report the Ðrst possible detection of J-band lines in infrared luminous galaxies in component A, H 2 which suggests a signiÐcant contribution of nonthermal excitation mechanisms.

show abstract

Star bursts and the extraordinary galaxy NGC 3690

Cited by 103 publications

References 0 publications

Inflowing gas onto a compact obscured nucleus in Arp 299A

Inflowing gas onto a compact obscured nucleus in Arp 299A

Star formation and AGN activity in a sample of local luminous infrared galaxies through multiwavelength characterization

Near‐Infrared Line Observations of Arp 299 as a Tracer of Activity in the Nuclei

Contact Info

Product

Resources

About