Close Galaxy pairs in Medium Density Regions: The Northern Sky

Nordgren, Tyler E.; Chengalur, Jayaram N.; Salpeter, E. E.; Terzian, Yervant

doi:10.1086/118454

Cited by 56 publications

(79 citation statements)

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“…5, and the measured line parameters are summarized in Table 2. There is no systematic velocity shift among the H 2 O lines and within 2σ all but one of the lines are consistent with the galaxy redshift of z = 0.010411 (Nordgren et al 1997). The H 2 O 139 µm 3 13 → 2 02 line has a possible blushifted line wing extending down to ∼ − 600 km s −1 , but this spectral range is noisy and the feature is at the 1σ-level.…”

Section: H 2 Osupporting

confidence: 64%

“…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. At a distance of 44.8 Mpc (linear scale: 217 pc/arcsec) (Fixsen et al 1996;Nordgren et al 1997, assum-ing H 0 = 73 km s −1 Mpc −1 ) the IR luminosity of the system is L IR ≈ 6.6 × 10 11 L ⊙ (Sanders et al 2003) of which Arp 299A contributes about 40 − 50% (Alonso-Herrero et al 2000;Charmandaris et al 2002).…”

Section: Introductionmentioning

confidence: 99%

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Inflowing gas onto a compact obscured nucleus in Arp 299A

Falstad¹,

González-Alfonso²,

Aalto³

et al. 2017

A&A

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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.

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Section: H 2 Osupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Inflowing gas onto a compact obscured nucleus in Arp 299A

Falstad¹,

González-Alfonso²,

Aalto³

et al. 2017

A&A

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“…The rising part at the end of the curve, seen on the blueshifted side, could be explained by the interaction with UGC 5972. The WHISP HI data clearly suffer from a technical problem since almost no signal was detected (see graphical overview on their Web site) whereas Nordgren et al (1997) have observed it with the VLA successfully when studying its interaction with its neighbour UGC 5972. They show that the disks of both galaxies are warped at the outer edges and that there is a tidal tail extending from UGC 5982 towards the NE, also they underline that the optical images show little sign of tidal interaction.…”

Section: Ugc 5982 (Ngc 3430)mentioning

confidence: 99%

GHASP: An Hα kinematic survey of spiral and irregular galaxies

Garrido

Marcelin

Amram

et al. 2002

A&A

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Abstract. GHASP (Gassendi Hα survey of SPirals) is a survey of Hα velocities in spiral and irregular galaxies. The observations began in 1998, with a scanning Fabry-Perot and a focal reducer attached at the Cassegrain focus of the 1.93 m telescope at the Observatoire de Haute-Provence. This paper presents the Hα maps, the 2D velocity fields and the rotation curves obtained for a set of 23 galaxies observed in October 1998 and April 1999. Most of them have already been observed in HI in the frame of the WHISP survey led at Westerbork, for which GHASP brings an interesting complement. The aim is to provide a reference sample of 2D velocity fields for about 200 nearby spiral galaxies at Hα wavelength.

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“…H  observations of NGC 7673 and its companion NGC 7677 (v r = 3554 km s −1 ) show that they have extended gas disks (Nordgren et al 1997). NGC 7673 is apparently faceon and fairly regular, with a mild asymmetry on the western edge; NGC 7677 has a small outer extension pointing towards NGC 7673.…”

Section: Properties Of Ngc 7673mentioning

confidence: 99%

The star cluster system of the NGC 7673 starburst

Homeier

Gallagher

Pasquali³

2002

A&A

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Abstract. We investigate the star cluster system in the starburst galaxy NGC 7673 using archival Hubble Space Telescope WFPC2 broad-band images. For the first time we are able to examine the internal structures of the prominent optical clumps in this galaxy. The clumps are composed of young stars, 16-33% of which are in bright star clusters. We identify 268 star cluster candidates in both the F555W and F814W images, and 50 clusters with the F255W filter. These data allow us to estimate ages and masses using color-magnitude and two-color diagrams for our sample. We find a population of young, <6 Myr clusters located throughout the galaxy with concentrations in the clumps. Star cluster mass estimates are 5-50 × 10 4 M for the brightest objects. The starburst remains active in physically well-separated regions, indicating a widespread starburst trigger. We discuss clump lifetimes, their implications for the future evolution of NGC 7673, and possible relationships to high redshift starbursts.

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Close Galaxy pairs in Medium Density Regions: The Northern Sky

Cited by 56 publications

References 0 publications

Inflowing gas onto a compact obscured nucleus in Arp 299A

Inflowing gas onto a compact obscured nucleus in Arp 299A

GHASP: An Hα kinematic survey of spiral and irregular galaxies

The star cluster system of the NGC 7673 starburst

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