Spectroscopic Observations of the Star Formation Activities in the Central Regions of Early-Type Spiral Galaxies

Usui, Tadashi; Saitō, Mamoru; Tomita, Akihiko

doi:10.1086/320389

Cited by 8 publications

(10 citation statements)

References 44 publications

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“…To plot real galaxies in Figure 1, we compile all morphological types of galaxies except for elliptical galaxies from the literature. In Figure 1, the filled circles are early-type spiral (Sa-Sab) galaxies observed by Usui, Saitō, & Tomita (2001), who selected active star-forming early-type spiral galaxies with . The filled squares, open squares, and log (L /L ) ≥ 0.5…”

Section: Resultsmentioning

confidence: 99%

Star Formation Rate from Dust Infrared Emission

Inoue

2002

The Astrophysical Journal

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We examine what types of galaxies the conversion formula from dust infrared (IR) luminosity into the star formation rate (SFR) derived by R. C. Kennicutt is applicable to. The ratio of the observed IR luminosity, , L IR to the intrinsic bolometric luminosity of the newly (Շ10 Myr) formed stars, , of a galaxy can be determined L SF by a mean dust opacity in the interstellar medium and the activity of the current star formation. We find that the area given by these parameters, , is very large, and many nearby normal and active star-0.5 ≤ L /L ≤ 2.0 IR SF forming galaxies really fall in this area. It results from offsetting two effects of a small dust opacity and a large cirrus contribution of normal galaxies relative to starburst galaxies on the conversion of the stellar emission into the dust IR emission. In conclusion, the SFR determined from the IR luminosity under the assumption of , like Kennicutt's, is reliable within a factor of 2 for all galaxies except for dust-rich but quiescent L p L IR SF galaxies and extremely dust-poor galaxies.

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Section: Resultsmentioning

confidence: 99%

Star Formation Rate from Dust Infrared Emission

Inoue

2002

The Astrophysical Journal

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“…There is a stellar bar oriented nearly along the minor axis of the galaxy that connects to a ring-like structure associated with a bump in the EW profile and decrease in the B − R colour profile. Bright regions of bar-induced shocked ionized gas are visible in the H α image, as well (Usui, Saitō & Tomita 2001).…”

Section: A4 Ngc 3729mentioning

confidence: 91%

“…The true dynamics of NGC 3729 are likely more complex than the azimuthally averaged circular velocities estimated from the tilted ring analysis. Usui et al (2001) found evidence for counter-rotating orbits in slit-spectroscopy oriented along the bar. Nonetheless, the estimated circular rotational velocities derived from the ionized gas velocity field are well described by the shape of the modelled stellar contribution to the observed rotation curve.…”

Section: A4 Ngc 3729mentioning

confidence: 93%

Baryonic distributions in galaxy dark matter haloes – II. Final results

Richards

Zee

Barnes

et al. 2018

Monthly Notices of the Royal Astronomical Society

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Re-creating the observed diversity in the organization of baryonic mass within dark matter haloes represents a key challenge for galaxy formation models. To address the growth of galaxy discs in dark matter haloes, we have constrained the distribution of baryonic and non-baryonic matter in a statistically representative sample of 44 nearby galaxies defined from the Extended Disk Galaxy Exploration Science (EDGES) Survey. The gravitational potentials of each galaxy are traced using rotation curves derived from new and archival radio synthesis observations of neutral hydrogen (H I). The measured rotation curves are decomposed into baryonic and dark matter halo components using 3.6 µm images for the stellar content, the H I observations for the atomic gas component, and, when available, CO data from the literature for the molecular gas component. The H I kinematics are supplemented with optical integral field spectroscopic (IFS) observations to measure the central ionized gas kinematics in 26 galaxies, including 13 galaxies that are presented for the first time in this paper. Distributions of baryonic-to-total mass ratios are determined from the rotation curve decompositions under different assumptions about the contribution of the stellar component and are compared to global and radial properties of the dominant stellar populations extracted from optical and near-infrared photometry. Galaxies are grouped into clusters of similar baryonic-to-total mass distributions to examine whether they also exhibit similar star and gas properties. The radial distribution of baryonic-to-total mass in a galaxy does not appear to correlate with any characteristics of its star formation history.

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“… a Optical classification (see text); references and notes: 1 Wu et al (1998); 2 Baan, Salzer & Lewinter (1998); 3 Veron‐Cetty & Veron (1986); 4 Usui, Saitō (2001); 5 García‐Barreto et al (1999); 6 Moorwood et al (1996); 7 Kewley et al (2000); 8 Smith et al (1998a); 9 the integrated line ration of UGC5101 are LINER‐like ( 2,8 ), but Gonçalves, Véron‐Cetty & Véron (1999) claim the detection of Sy‐like optical signatures after a multi‐component fitting analysis; 10 the integrated line ratios of NGC 1672 are H ii ‐like ( 7 ), but Veron, Veron & Zuiderwijk (1981) claim the detection of Sy‐like optical signatures after a multi‐component fitting analysis; 11 Phillips (1993) dismissed previous claims for the presence of Sy‐like signatures in the optical spectrum; 12 Moran, Halpern & Helfand (1996); 13 Lehnert & Heckman (1995). …”

Section: X‐ray Identification Of Elusive Agnmentioning

confidence: 99%

Elusive active galactic nuclei

Maiolino

Comastri

Gilli

et al. 2003

Monthly Notices RAS

147

157

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A fraction of active galactic nuclei do not show the classical Seyfert‐type signatures in their optical spectra, i.e. they are optically ‘elusive’. X‐ray observations are an optimal tool to identify this class of objects. We combine new Chandra observations with archival X‐ray data in order to obtain a first estimate of the fraction of elusive active galactic nuclei (AGN) in local galaxies and to constrain their nature. Our results suggest that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei. Most elusive AGN are heavily absorbed in the X‐rays, with gas column densities exceeding 1024 cm−2, suggesting that their peculiar nature is associated with obscuration. It is likely that in elusive AGN the nuclear UV source is completely embedded and the ionizing photons cannot escape, which prevents the formation of a classical narrow‐line region. Elusive AGN may contribute significantly to the 30‐keV bump of the X‐ray background.

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Spectroscopic Observations of the Star Formation Activities in the Central Regions of Early-Type Spiral Galaxies

Cited by 8 publications

References 44 publications

Star Formation Rate from Dust Infrared Emission

Star Formation Rate from Dust Infrared Emission

Baryonic distributions in galaxy dark matter haloes – II. Final results

Elusive active galactic nuclei

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