Accurate Stellar Population Studies from Multiband Photometric Observations

Romaniello, M.; Panagia, N.; Scuderi, S.; Kirshner, R.

doi:10.1086/338430

Cited by 39 publications

(79 citation statements)

References 19 publications

(21 reference statements)

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“…the reviews by Preibisch 2012; and Soderblom et al 2013). From a theoretical point of view, while the absolute ages of PMS stars are only as good as the isochrones allow, relative ages are always better defined than a factor of two for ages up to ∼30 Myr, as already shown by Romaniello et al (2002) andDa Rio et al (2010). From an observational point of view, the colours and magnitudes of the stars are affected by uncertainties induced by inaccurate evaluation of differential extinction, stellar variability (Herbst et al 2002) and complex physical processes like episodic accretion (Baraffe et al 2009).…”

Section: Physical Parameters Of the Pms Starsmentioning

confidence: 77%

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Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

Beccari¹,

Marchi²,

Panagia³

et al. 2015

A&A

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We present a study of the mass accretion rates of pre-main sequence (PMS) stars in the cluster Trumpler 14 (Tr 14) in the Carina Nebula. Using optical multiband photometry we were able to identify 356 PMS stars showing Hα excess emission with equivalent width EW(Hα) > 20 Å. We interpret this observational feature as an indication that these objects are still actively accreting gas from their circumstellar medium. From a comparison of the HR diagram with PMS evolutionary models we derive ages and masses of the PMS stars. We find that most of the PMS objects are younger than 10 Myr with a median age of ∼3 Myr. Surprisingly, we also find that ∼20% of the mass accreting objects are older than 10 Myr. For each PMS star in Trumpler 14 we determine the mass accretion rate (Ṁ acc ) and discuss its dependence on mass and age. We finally combine the optical photometry with near-IR observations to build the spectral energy distribution (SED) for each PMS star in Tr 14. The analysis of the SEDs suggests the presence of transitional discs in which a large amount of gas is still present and sustains accretion onto the PMS object at ages older than 10 Myr. Our results, discussed in light of recent recent discoveries with Herschel of transitional discs containing a massive gas component around the relatively old PMS stars TW Hydrae, 49 Ceti, and HD 95086, support a new scenario n which old and evolved debris discs still host a significant amount of gas.

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Section: Physical Parameters Of the Pms Starsmentioning

confidence: 77%

“…8 to derive a reliable measure of the mass and age (see Romaniello et al 1998, for details on the method used, with an approach similar to the one more recently presented by Da Rio et al 2012). Mass and age distributions for the PMS objects are shown in the upper and lower panels of Fig.…”

Section: Physical Parameters Of the Pms Starsmentioning

confidence: 99%

Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

Beccari¹,

Marchi²,

Panagia³

et al. 2015

A&A

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“…To this purpose we created energy distributions of stellar atmosphere models and analysed them in the same way in which we analysed the energy distributions of clusters. We adopt the supergiant models calculated by Bessell et al (1998), transformed to WFPC2 magnitudes by Romaniello et al (2002). Bessell et al (1998) normalized the magnitudes to stars with a radius of 1 R at a distance of 10 pc.…”

Section: The Elimination Of Stars On the Basis Of Their Energy Distrimentioning

confidence: 99%

The star cluster population of M 51

Gieles¹,

Bastian²,

Lamers³

2005

A&A

196

277

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Abstract. We use archival Hubble Space Telescope observations of broad-band images from the ultraviolet (F255W-filter) through the near infrared (NICMOS F160W-filter) to study the star cluster population of the interacting spiral galaxy M 51. We obtain age, mass, extinction, and effective radius estimates for 1152 star clusters in a region of ∼7.3 × 8.1 kpc centered on the nucleus and extending into the outer spiral arms. In this paper we present the data set and exploit it to determine the age distribution and relationships among the fundamental parameters (i.e. age, mass, effective radius). We show the critical dependence of the age distribution on the sample selection, and confirm that using a constant mass cut-off, above which the sample is complete for the entire age range of interest, is essential. In particular, in this sample we are complete only for masses above 5 × 10 4 M for the last 1 Gyr. Using this dataset we find: i) that the cluster formation rate seems to have had a large increase ∼50−70 Myr ago, which is coincident with the suggested second passage of its companion, NGC 5195; ii) a large number of extremely young (<10 Myr) star clusters, which we interpret as a population of unbound clusters of which a large majority will disrupt within the next ∼10 Myr; and iii) that the distribution of cluster sizes can be well approximated by a power-law with exponent, −η = −2.2 ± 0.2, which is very similar to that of Galactic globular clusters, indicating that cluster disruption is largely independent of cluster radius. In addition, we have used this dataset to search for correlations among the derived parameters. In particular, we do not find any strong trends between the age and mass, mass and effective radius, nor between the galactocentric distance and effective radius. There is, however, a strong correlation between the age of a cluster and its extinction, with younger clusters being more heavily reddened than older clusters.

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“…Normally the R-band is used as the continuum for the Hα filter. De showed for the field around SN 1987A (Romaniello et al 1998;Panagia et al 2000;Romaniello et al 2002) that the Advanced Camera for Surveys (ACS, Ubeda et al 2012) filters F 555W and F 814W can be similarly used to obtain the continuum for the Hα filter. Up to now, this method has been proven to be successful in studies for different clusters, such as NGC 346 in the Small Magellanic Cloud (SMC, De Marchi et al 2011a) and NGC 3603 in the MW (Beccari et al 2010).…”

Section: Introductionmentioning

confidence: 99%

A High-Resolution Multiband Survey of Westerlund 2 With the Hubble Space Telescope. Ii. Mass Accretion in the Pre-Main-Sequence Population

Zeidler

Grebel

Nota

et al. 2016

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We present a detailed analysis of the pre-main-sequence (PMS) population of the young star cluster Westerlund 2 (Wd2), the central ionizing cluster of the H II region RCW 49, using data from a high resolution multi-band survey with the Hubble Space Telescope. The data were acquired with the Advanced Camera for Surveys in the F 555W , F 814W , and F 658N filters and with the Wide Field Camera 3 in the F 125W , F 160W , and F 128N filters. We find a mean age of the region of 1.04 ± 0.72 Myr. The combination of dereddened F 555W and F 814W photometry in combination with F 658N photometry allows us to study and identify stars with Hα excess emission. With a careful selection of 240 bona-fide PMS Hα excess emitters we were able to determine their Hα luminosity, which has a mean value L(Hα) = 1.67 · 10 −31 erg s −1 . Using the PARSEC 1.2S isochrones to obtain the stellar parameters of the PMS stars we determined a mean mass accretion rateṀ acc = 4.43 · 10 −8 M ⊙ yr −1 per star. A careful analysis of the spatial dependence of the mass-accretion rate suggests that this rate is ∼ 25% lower in center of the two density peaks of Wd2 in close proximity to the luminous OB stars, compared to the Wd2 average. This rate is higher with increasing distance from the OB stars, indicating that the PMS accretion disks are being rapidly destroyed by the farultra-violet radiation emitted by the OB population.

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Accurate Stellar Population Studies from Multiband Photometric Observations

Cited by 39 publications

References 19 publications

Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

The star cluster population of M 51

A High-Resolution Multiband Survey of Westerlund 2 With the Hubble Space Telescope. Ii. Mass Accretion in the Pre-Main-Sequence Population

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