Characteristics of Star-Forming Regions in the Advanced Minor-Merger, Luminous Infrared Galaxy NGC 4194

Weistrop, D.; Nelson, Charles R.; Angione, Ronald J.; Bachilla, R.; Hancock, Mark H.; Kaiser, M. E.

doi:10.1088/0004-6256/143/4/98

Cited by 9 publications

(7 citation statements)

References 56 publications

(87 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…That study also measures ne using a spatially-integrated stack of 14 galaxies, and the resulting [S II] ratios may be sensitive to regions outside the main starburst of these systems. Many local studies of (U)LIRG/starburst systems find elevated electron densities (ne 300 cm −3 ) in the central star-forming regions (e.g., Armus et al 1989;Lehnert & Heckman 1996;Weistrop et al 2012;Arribas et al 2014), as well as large declines in ne with radius. These high central densities and radial dependences suggest measuring ne in a spatially-resolved fashion may be important for constraining the densities of the starburst region.…”

Section: Discussionmentioning

confidence: 99%

Supernova-driven outflows in NGC 7552: a comparison of H α and UV tracers

Wood

Tremonti

Calzetti

et al. 2015

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We investigate the supernova-driven galactic wind of the barred spiral galaxy NGC 7552, using both ground-based optical nebular emission lines and far-ultraviolet absorption lines measured with the Hubble Space Telescope Cosmic Origins Spectrograph. We detect broad (∼ 300 km s −1 ) blueshifted (−40 km s −1 ) optical emission lines associated with the galaxy's kpc-scale star-forming ring. The broad line kinematics and diagnostic line ratios suggest that the H α emission comes from clouds of high density gas entrained in a turbulent outflow. We compare the H α emission line profile to the UV absorption line profile measured along a coincident sight line and find significant differences. The maximum blueshift of the H α-emitting gas is ∼ 290 km s −1 , whereas the UV line profile extends to blueshifts upwards of 1000 km s −1 . The mass outflow rate estimated from the UV is roughly nine times greater than that estimated from H α. We argue that the H α emission traces a cluster-scale outflow of dense, low velocity gas at the base of the large-scale wind. We suggest that UV absorption line measurements are therefore more reliable tracers of warm gas in starburst-driven outflows.

show abstract

Section: Discussionmentioning

confidence: 99%

Supernova-driven outflows in NGC 7552: a comparison of H α and UV tracers

Wood

Tremonti

Calzetti

et al. 2015

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…Spectroscopic Hα observations find the majority of the star formation going on in the central 8 (Weistrop et al 2012). Several star forming clusters have been identified in the UV (160 nm and 200 nm, Weistrop et al 2004) and the VIS (430 nm and 780 nm, Hancock et al 2006); some of them are associated with the AGN at the nucleus of NGC 4194 (Fig.…”

Section: Circumnuclear Molecular Gas and Star Formationmentioning

confidence: 98%

“…The CO 1−0, radio continuum (at 3.5 cm, 6 cm and 20 cm), and HST observations (e.g., at wavelengths of 150 nm and 600 nm), for example, show brightness distribution peaks at the location of the AGN (e.g., Aalto & Hüttemeister 2000;Condon et al 1990;Beswick et al 2005;Armus et al 1990;Weistrop et al 2004). Spectroscopic Hα observations find the majority of the star formation going on in the central 8 (Weistrop et al 2012). Several star forming…”

Section: Circumnuclear Molecular Gas and Star Formationmentioning

confidence: 99%

Molecular tendrils feeding star formation in the Eye of the Medusa

König

Aalto

Lindroos

et al. 2014

A&A

View full text Add to dashboard Cite

Studying molecular gas properties in merging galaxies gives us important clues to the onset and evolution of interaction-triggered starbursts. NGC 4194 (the Medusa merger) is particularly interesting to study, since its FIR-to-CO luminosity ratio rivals that of ultraluminous galaxies (ULIRGs), despite its lower luminosity compared to ULIRGs, which indicates a high star formation efficiency (SFE) that is relative to even most spirals and ULIRGs. We study the molecular medium at an angular resolution of 0.65 × 0.52 (∼120 × 98 pc) through our observations of 12 CO 2−1 emission using the Submillimeter Array (SMA). We compare our 12 CO 2−1 maps with the optical Hubble Space Telescope and high angular resolution radio continuum images to study the relationship between molecular gas and the other components of the starburst region. The molecular gas is tracing the complicated dust lane structure of NGC 4194 with the brightest emission being located in an off-nuclear ring-like structure with ∼320 pc radius, the Eye of the Medusa. The bulk CO emission of the ring is found south of the kinematical center of NGC 4194. The northern tip of the ring is associated with the galaxy nucleus, where the radio continuum has its peak. Large velocity widths associated with the radio nucleus support the notion of NGC 4194 hosting an active galactic nucleus. A prominent, secondary emission maximum in the radio continuum is located inside the molecular ring. This suggests that the morphology of the ring is partially influenced by massive supernova explosions. From the combined evidence, we propose that the Eye of the Medusa contains a shell of swept up material where we identify a number of giant molecular associations. We propose that the Eye may be the site of an efficient starburst of 5−7 M yr −1 , but it would still constitute only a fraction of the 30−50 M yr −1 star formation rate of the Medusa. Furthermore, we find that ∼50% of the molecular mass of NGC 4194 is found in extended filamentary-like structures tracing the minor and major axis dust lanes. We suggest that molecular gas is transported along these lanes, providing the central starburst region with fuel. Interestingly, a comparison with locations of super star clusters (SSCs) reveal that the molecular gas and the SSCs are not co-spatial.

show abstract

“…It has a single nucleus and a near-infrared K band light profile that approximately fits an R 1/4 profile (Rothberg & Joseph 2004). Arp 160 has variously been classified as a minor merger, the product of a disk galaxy falling into a larger elliptical (Manthey et al 2008;Weistrop et al 2012), and as a major merger (Rothberg & Fisher 2010). In the current study, we assume it is the result of an approximately equal mass merger, and classify it as merger stage 5.…”

Section: Appendix: Notes On Individual Galaxies In the Samplementioning

confidence: 99%

Diffuse X-Ray-emitting Gas in Major Mergers

Smith

Campbell

Struck

et al. 2018

View full text Add to dashboard Cite

Using archived data from the Chandra X-ray telescope, we have extracted the diffuse Xray emission from 49 equal-mass interacting/merging galaxy pairs in a merger sequence, from widely separated pairs to merger remnants. After removal of contributions from unresolved point sources, we compared the diffuse thermal X-ray luminosity from hot gas (L X (gas)) with the global star formation rate (SFR). After correction for absorption within the target galaxy, we do not see strong trend of L X (gas)/SFR with SFR or merger stage for galaxies with SFR > 1 M ⊙ yr −1 . For these galaxies, the median L X (gas)/SFR is 5.5 × 10 39 ((erg s −1 )/M ⊙ yr −1 )), similar to that of normal spiral galaxies. These results suggest that stellar feedback in star forming galaxies reaches an approximately steady state condition, in which a relatively constant fraction of about 2% of the total energy output from supernovae and stellar winds is converted into X-ray flux. Three late-stage merger remnants with low SFRs and high K band luminosities (L K ) have enhanced L X (gas)/SFR; their UV/IR/optical colors suggest that they are post-starburst galaxies, perhaps in the process of becoming ellipticals. Systems with L K < 10 10 L ⊙ have lower L X (gas)/SFR ratios than the other galaxies in our sample, perhaps due to lower gravitational fields or lower metallicities. We see no relation between L X (gas)/SFR and Seyfert activity in this sample, suggesting that feedback from active galactic nuclei is not a major contributor to the hot gas in our sample galaxies.

show abstract

Characteristics of Star-Forming Regions in the Advanced Minor-Merger, Luminous Infrared Galaxy NGC 4194

Cited by 9 publications

References 56 publications

Supernova-driven outflows in NGC 7552: a comparison of H α and UV tracers

Supernova-driven outflows in NGC 7552: a comparison of H α and UV tracers

Molecular tendrils feeding star formation in the Eye of the Medusa

Diffuse X-Ray-emitting Gas in Major Mergers

Contact Info

Product

Resources

About