Hα emission line morphologies in Markarian starburst galaxies

Chitre, A.; Joshi, U.

doi:10.1007/bf02702254

Cited by 2 publications

(3 citation statements)

References 17 publications

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“…The distribution peaks at ∼ 1 kpc, with three quarter of the galaxies presenting effective radii smaller than 3 kpc. The median value is almost identical (ours is 0.02dex larger) to that found by Lehnert & Heckman (1996) for a sample of edge-on, infrared-warm, starburst galaxies, and ∼ 15% larger than the values given by Chitre & Joshi (2001) for a sample of Markarian galaxies. The distribution of effective radii in the R C -band is also presented in this figure.…”

Section: Concentration and Size Propertiessupporting

confidence: 84%

“…(2) shedding light on the influence of the environment on star formation by studying samples of field galaxies, compact groups, and clusters (Gavazzi et al 1998;Iglesias-Páramo & Vílchez 1999;Hameed & Devereux 1999); (3) extending the analysis to galaxies with enhanced star formation (Conselice et al 2000b;Chitre & Joshi 2001). These studies demonstrate that the use of Hα photometry can be extremely useful in the characterization of the youngest stellar population in star-forming galaxies, and in complementing spectroscopic observations.…”

Section: Introductionmentioning

confidence: 99%

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Spatial Analysis of the Hα Emission in the Local Star‐forming UCM Galaxies

Pérez‐González

Zamorano

Gallego

et al. 2003

ApJ

106

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We present a photometric study of the Hα emission in the Universidad Complutense de Madrid (UCM) Survey galaxies. This work complements our previously-published spectroscopic data. We study the location of the starforming knots, their intensity, concentration, and the relationship of these properties with those of the host galaxy. We also estimate that the amount of Hα emission that arises from the diffuse ionized gas is about 15-30% of the total Hα flux for a typical UCM galaxy. This percentage seems to be independent of the Hubble type. Conversely, we found that an 'average' UCM galaxy harbours a star formation event with 30% of its Hα luminosity arising from a nuclear component. The implications of these results for higher-redshift studies are discussed, including the effects of galaxy size and the depth of the observations. A correlation between the SFR and the Balmer decrement is observed, but such correlation breaks down for large values of the extinction. Finally, we recalculate the Hα luminosity function and star formation rate density of the local Universe using the new imaging 1 pag@astrax.fis.ucm.es -2data. Our results point out that, on average, spectroscopic observations detected about one third of the total emission-line flux of a typical UCM galaxy. The new values obtained for the Hα luminosity density and the star formation rate density of the local Universe are 10 39.3±0.2 erg s −1 Mpc −3 , and ρ SF R = 0.016 +0.007 −0.004 M ⊙ yr −1 Mpc −3 (H 0 = 50 km s −1 Mpc −1 , Ω M = 1.0, Λ = 0). The corresponding values for the 'concordance cosmology' (H 0 = 70 km s −1 Mpc −1 , Ω M = 0.3, Λ = 0.7) are 10 39.5±0.2 erg s −1 Mpc −3 ρ SF R = 0.029 +0.008 −0.005 M ⊙ yr −1 Mpc −3 .

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Section: Concentration and Size Propertiessupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Spatial Analysis of the Hα Emission in the Local Star‐forming UCM Galaxies

Pérez‐González

Zamorano

Gallego

et al. 2003

ApJ

106

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“…Kennicutt (1984) has remarked that the emission measure of individual H  regions follows a scalable exponential profile. This was found to also approximate well the surface brightness profiles of H  regions in nearby face-on galaxies (Rozas et al 1988) and of the Hα halo of several Markarian starburst galaxies (Chitre & Joshi 2001).…”

Section: The Ionized Gas Component Of I Zw 18supporting

confidence: 74%

The blue compact dwarf galaxy I Zw 18: A comparative study of its low-surface-brightness component

Papaderos

Izotov

Thuan

et al. 2002

A&A

119

192

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Abstract. Using HST and ground-based optical and NIR imaging data , , we investigate whether the blue compact dwarf (BCD) galaxy I Zw 18 possesses an extended low-surface-brightness (LSB) old stellar population underlying its star-forming regions, as is the case in the majority of BCDs. This question is central to the long-standing debate on the evolutionary state of I Zw 18. We show that the exponential intensity decrease observed in the filamentary LSB envelope of the BCD out to > ∼ 18 ( > ∼ 1.3 kpc assuming a distance of 15 Mpc) is not due to an evolved stellar disc underlying its star-forming regions, but rather, due to extended ionized gas emission. Ionized gas accounts for more than 80% of the line-of-sight emission at a galactocentric distance of ∼0.65 kpc (∼3 effective radii), and for > ∼ 30% to 50% of the R light of the main body of I Zw 18. Broad-band images reveal, after subtraction of nebular line emission, a relatively smooth stellar host extending slightly beyond the star-forming regions. This unresolved stellar component, though very compact, is not exceptional for intrinsically faint dwarfs with respect to its structural properties. However, being blue over a radius range of ∼5 exponential scale lengths and showing little colour contrast to the star-forming regions, it differs strikingly from the red LSB host of standard BCDs. This fact, together with the comparably blue colours of the faint C component, ∼1.6 kpc away from the main body of I Zw 18, suggests that the formation of I Zw 18 as a whole has occurred within the last 0.5 Gyr, making it a young BCD candidate. Furthermore, we show that the ionized envelope of I Zw 18 is not exceptional among star-forming dwarf galaxies, neither by its exponential intensity fall-off nor by its scale length. However, contrary to evolved BCDs, the stellar LSB component of I Zw 18 is much more compact than the ionized gas envelope. In the absence of an appreciable underlying stellar population, extended ionized gas emission dominates in the outer parts of I Zw 18, mimicking an exponential stellar disc on optical surface brightness profiles.

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Hα emission line morphologies in Markarian starburst galaxies

Cited by 2 publications

References 17 publications

Spatial Analysis of the Hα Emission in the Local Star‐forming UCM Galaxies

Spatial Analysis of the Hα Emission in the Local Star‐forming UCM Galaxies

The blue compact dwarf galaxy I Zw 18: A comparative study of its low-surface-brightness component

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