The H<i>α</i>galaxy survey

James, P. A.; Bretherton, Charlotte; Knapen, Johan H.

doi:10.1051/0004-6361/200810715

Cited by 73 publications

(90 citation statements)

References 62 publications

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“…To make this point more quantitative, we have estimated the fraction of total SF that might be expected in an unbarred galaxy in the radial range covered by the extracted SFD slit spectra for each of the 4 galaxies studied. This was done using averaged Hα profiles for unbarred galaxies of the same Hubble T -type (Sb or Sa), taken from James, Bretherton, & Knapen (2009). The resulting fractions are: for NGC 2543, 33 per cent; for NGC 2712, 26 per cent; for NGC 3185, 37 per cent; and for NGC 3351, 15 per cent, with the smaller value for the last galaxy being due to its shorter bar.…”

Section: Discussionmentioning

confidence: 99%

Stellar population constraints on the ages of galactic bars

James

Percival

2016

Mon. Not. R. Astron. Soc.

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We present a study of the stellar populations within the central regions of four nearby barred galaxies, and use a novel technique to constrain the duration of bar activity. We focus on the star formation 'desert', a region within each of these galaxies where star formation appears to have been suppressed by the bar. New Hβ spectroscopic data are presented, and used to produce spectroscopic line indices which are compared with theoretical predictions from population synthesis models for simple stellar populations and temporally truncated star formation histories. This analysis shows that the dearth of star formation activity in these regions appears to have been continuing for at least 1 Gyr, with timescales of several Gyr indicated for two of the galaxies. This favours models in which strong bars can be long-lived features of galaxies, but our results also indicate a significant diversity in stellar population ages, and hence in the implied histories of bar activity in these four galaxies.

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Section: Discussionmentioning

confidence: 99%

Stellar population constraints on the ages of galactic bars

James

Percival

2016

Mon. Not. R. Astron. Soc.

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“…However, these two phenomena are probably unrelated. James et al (2009) studied the radial distribution of Hα emission in a large sample of spiral galaxies and found that the late-type spirals (Sc+) show a Hα flux deficit in the bulge regardless of the presence of bars. This effect is much less pronounced in the Sa-type spirals or even absent in their barred counterparts, which tend to have a high concentration of the Hα emission toward the center.…”

Section: Hα Flux Extinction and Star Formation Ratementioning

confidence: 99%

“…According to James et al (2009), there is a significant difference in the Hα radial profile of barred and unbarred Sb galaxies. The unbarred Sb galaxies show a smooth profile similar to Sa galaxies.…”

Section: Hα Flux Extinction and Star Formation Ratementioning

confidence: 99%

Type Ia supernova host galaxies as seen with IFU spectroscopy

Stanishev¹,

Rodrigues

Mourão³

et al. 2012

A&A

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Context. Type Ia supernovae (SNe Ia) have been widely used in cosmology as distance indicators. However, to fully exploit their potential in cosmology, a better control over systematic uncertainties is required. Some of the uncertainties are related to the unknown nature of the SN Ia progenitors. Aims. We aim to test the use of integral field unit (IFU) spectroscopy for correlating the properties of nearby SNe Ia with the properties of their host galaxies at the location of the SNe. The results are to be compared with those obtained from an analysis of the total host spectrum. The goal is to explore this path of constraining the nature of the SN Ia progenitors and further improve the use of SNe Ia in cosmology. Methods. We used the wide-field IFU spectrograph PMAS/PPAK at the 3.5 m telescope of Calar Alto Observatory to observe six nearby spiral galaxies that hosted SNe Ia. Spatially resolved 2D maps of the properties of the ionized gas and the stellar populations were derived. Results. Five of the observed galaxies have an ongoing star formation rate of 1-5 M yr −1 and mean stellar population ages ∼5 Gyr. The sixth galaxy shows no star formation and has an about 12 Gyr old stellar population. All galaxies have stellar masses larger than 2 × 10 10 M and metallicities above solar. Four galaxies show negative radial metallicity gradients of the ionized gas up to −0.058 dex kpc −1 and one has nearly uniform metallicity with a possible shallow positive slope. The stellar components show shallower negative metallicity gradients up to −0.03 dex kpc −1 . We find no clear correlation between the properties of the galaxy and those of the supernovae, which may be because of the small ranges spanned by the galaxy parameters. However, we note that the Hubble residuals are on average positive while negative Hubble residuals are expected for SNe Ia in massive hosts such as the galaxies in our sample. Conclusions. The IFU spectroscopy on 4-m telescopes is a viable technique for studying host galaxies of nearby SNe Ia. It allows one to correlate the supernova properties with the properties of their host galaxies at the projected positions of the supernovae. Our current sample of six galaxies is too small to draw conclusions about the SN Ia progenitors or correlations with the galaxy properties, but the ongoing CALIFA IFU survey will provide a solid basis to exploit this technique more and improve our understanding of SNe Ia as cosmological standard candles.

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“…Although the general overview of the impact of a bar on a galactic disc is well accepted, the details of the process, and its dependence on galactic properties, pose many remaining questions. While the presence of a bar often causes an increase of the SFR, several observations show no increase (Pompea & Rieke 1990;Martinet & Friedli 1997;Chapelon et al 1999) or an increase only in early-type spiral galaxies (Ho et al 1997;James et al 2009). Recent work with the volunteer-based identification of morphological types by the Galaxy Zoo team showed that the specific star formation rate (SSFR) is anti-correlated with the presence of a bar (Cheung et al 2013) but at same time the relation between the SFR and the stellar mass M * seems unaffected by the presence of a bar (Willett et al 2015).…”

Section: Introductionmentioning

confidence: 99%

The mass dependence of star formation histories in barred spiral galaxies

Carles¹,

Martel²,

Ellison³

et al. 2016

Mon. Not. R. Astron. Soc.

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We performed a series of 29 gasdynamical simulations of disc galaxies, barred and unbarred, with various stellar masses, to study the impact of the bar on star formation history. Unbarred galaxies evolve very smoothly, with a star formation rate (SFR) that varies by at most a factor of three over a period of 2 Gyr. The evolution of barred galaxies is much more irregular, especially at high stellar masses. In these galaxies, the bar drives a substantial amount of gas toward the centre, resulting in a high SFR, and producing a starburst in the most massive galaxies. Most of the gas is converted into stars, and gas exhaustion leads to a rapid drop of star formation after the starburst. In massive barred galaxies (stellar mass M * > 2 × 10 10 M ⊙ ) the large amount of gas funnelled toward the centre is completely consumed by the starburst, while in lower-mass barred galaxies it is only partially consumed. Gas concentration is thus higher in lower-mass barred galaxies than it is in higher-mass ones. Even though unbarred galaxies funnelled less gas toward their centre, the lower SFR allows this gas to accumulate. At late times, the star formation efficiency is higher in barred galaxies than unbarred ones, enabling these galaxies to maintain a higher SFR with a smaller gas supply. Several properties, such as the global SFR, central SFR, or central gas concentration, vary monotonically with time for unbarred galaxies, but not for barred galaxies. Therefore one must be careful when comparing barred and unbarred galaxies that share one observational property, since these galaxies might be at very different stages of their respective evolution.

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The Hαgalaxy survey

Cited by 73 publications

References 62 publications

Stellar population constraints on the ages of galactic bars

Stellar population constraints on the ages of galactic bars

Type Ia supernova host galaxies as seen with IFU spectroscopy

The mass dependence of star formation histories in barred spiral galaxies

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