The Star Formation History of the Large Magellanic Cloud

Harris, Jason; Zaritsky, Dennis

doi:10.1088/0004-6256/138/5/1243

Cited by 461 publications

(586 citation statements)

References 69 publications

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“…The Commander free-free amplitude at 10 GHz is 141 Jy, which gives an SFR of 0.10 M yr −1 ; the LSF model gives 0.08 M yr −1 , and the LSF-CMB model gives 0.09 M yr −1 . These are lower than the estimate of 0.2 M yr −1 for the average SFR from analyses of stellar populations by Harris & Zaritsky (2009) and Rezaeikh et al (2014), but agree well with the recent star formation rate of 0.06 M yr −1 calculated by Whitney et al (2008) based on young stellar objects; these authors also give a range of SFR estimates of 0.05-0.25 M yr −1 from infrared and Hα data. However, all of these estimates correspond to an SFR over different timescales (e.g., Murphy et al 2012), as well as being subject to systematic effects; a more detailed study would be necessary to disentangle these effects.…”

Section: Lmc and Smcsupporting

confidence: 88%

Planck2015 results

Ade

Aghanim

Alves

et al. 2016

A&A

165

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We discuss the Galactic foreground emission between 20 and 100 GHz based on observations by Planck and WMAP. The total intensity in this part of the spectrum is dominated by free-free and spinning dust emission, whereas the polarized intensity is dominated by synchrotron emission. The Commander component-separation tool has been used to separate the various astrophysical processes in total intensity. Comparison with radio recombination line templates verifies the recovery of the free-free emission along the Galactic plane. Comparison of the high-latitude Hα emission with our free-free map shows residuals that correlate with dust optical depth, consistent with a fraction (≈30%) of Hα having been scattered by high-latitude dust. We highlight a number of diffuse spinning dust morphological features at high latitude. There is substantial spatial variation in the spinning dust spectrum, with the emission peak (in I ν ) ranging from below 20 GHz to more than 50 GHz. There is a strong tendency for the spinning dust component near many prominent H ii regions to have a higher peak frequency, suggesting that this increase in peak frequency is associated with dust in the photo-dissociation regions around the nebulae. The emissivity of spinning dust in these diffuse regions is of the same order as previous detections in the literature. Over the entire sky, the Commander solution finds more anomalous microwave emission (AME) than the WMAP component maps, at the expense of synchrotron and free-free emission. This can be explained by the difficulty in separating multiple broadband components with a limited number of frequency maps. Future surveys, particularly at 5-20 GHz, will greatly improve the separation by constraining the synchrotron spectrum. We combine Planck and WMAP data to make the highest signal-to-noise ratio maps yet of the intensity of the all-sky polarized synchrotron emission at frequencies above a few GHz. Most of the high-latitude polarized emission is associated with distinct large-scale loops and spurs, and we re-discuss their structure. We argue that nearly all the emission at 40 • > l > −90 • is part of the Loop I structure, and show that the emission extends much further in to the southern Galactic hemisphere than previously recognised, giving Loop I an ovoid rather than circular outline. However, it does not continue as far as the "Fermi bubble/microwave haze", making it less probable that these are part of the same structure. We identify a number of new faint features in the polarized sky, including a dearth of polarized synchrotron emission directly correlated with a narrow, roughly 20 • long filament seen in Hα at high Galactic latitude. Finally, we look for evidence of polarized AME, however many AME regions are significantly contaminated by polarized synchrotron emission, and we find a 2σ upper limit of 1.6% in the Perseus region.

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Section: Lmc and Smcsupporting

confidence: 88%

Planck2015 results

Ade

Aghanim

Alves

et al. 2016

A&A

165

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“…Based on size-of-sample effects (e.g., Gieles & Bastian 2008) we would expect that the SFR of the LMC was ∼ 4 times higher while the eMSTO clusters were forming (c.f., Maschberger & Kroupa 2011). However, no such increase in the SFH, based on resolved stars, is seen from 1 − 2 Gyr ago relative to today in the LMC (e.g., Harris & Zaritsky 2009;Weisz et al 2013). The lack of increase in the SFH from 1 − 2 Gyr is consistent with the fact that the clusters in this age range would have been born with similar masses (at the upper end of the mass function) as that observed in the YMCs in the LMC today.…”

Section: Discussionmentioning

confidence: 98%

The morphology of the sub-giant branch and red clump reveal no sign of age spreads in intermediate-age clusters

Bastian

Niederhofer

2015

Monthly Notices of the Royal Astronomical Society

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A recent surprise in stellar cluster research, made possible through the precision of Hubble Space Telescope photometry, was that some intermediate age (1 − 2 Gyr) clusters in the Large and Small Magellanic Clouds have main sequence turn-off (MSTO) widths that are significantly broader than would be expected for a simple stellar population (SSP). One interpretation of these extended MSTOs (eMSTOs) is that age spreads of the order of ∼ 500 Myr exist within the clusters, radically redefining our view of stellar clusters, which are traditionally thought of as single age, single metallicity stellar populations. Here we test this interpretation by studying other regions of the CMD that should also be affected by such large age spreads, namely the width of the sub-giant branch (SGB) and the red clump (RC). We study two massive clusters in the LMC that display the eMSTO phenomenon (NGC 1806 & NGC 1846) and show that both have SGB and RC morphologies that are in conflict with expectations if large age spreads exist within the clusters. We conclude that the SGB and RC widths are inconsistent with extended star-formation histories within these clusters, hence age spreads are not likely to be the cause of the eMSTO phenomenon. Our results are in agreement with recent studies that also have cast doubt on whether large age spreads can exist in massive clusters; namely the failure to find age spreads in young massive clusters, a lack of gas/dust detected within massive clusters, and homogeneous abundances within clusters that exhibit the eMSTO phenomenon.

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“…The spiral galaxy is characterized by a continuous SFR which is higher than the one of irregulars. The models are able to reproduce the present day SFR observed in irregulars (Chomiuk & Povich 2011) and spirals (Harris & Zaritsky 2009). In the other panels of the Figure, the evolution of various processes related to dust evolution (stellar production, accretion, and destruction) are shown.…”

Section: The Reference Modelsmentioning

confidence: 90%

The cosmic dust rate across the Universe

Gioannini¹,

Matteuccí

Calura

2017

Monthly Notices of the Royal Astronomical Society

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We investigate the evolution of interstellar dust in the Universe by means of chemical evolution models of galaxies of different morphological types, reproducing the main observed features of present day galaxies. We adopt the most updated prescriptions for dust production from supernovae and asymptotic giant branch (AGB) stars as well as for dust accretion and destruction processes. Then, we study the cosmic dust rate in the framework of three different cosmological scenarios for galaxy formation: i) a pure luminosity scenario (PLE), ii) a number density evolution scenario (DE), as suggested by the classical hierarchical clustering scenario and iii) an alternative scenario, in which both spirals and ellipticals are allowed to evolve in number on an observationally motivated basis. Our results give predictions about the evolution of the dust content in different galaxies as well as the cosmic dust rate as a function of redshift. Concerning the cosmic dust rate, the best scenario is the alternative one, which predicts a peak at 2 < z < 3 and reproduces the cosmic star formation rate. We compute the evolution of the comoving dust density parameter Ω dust and find agreement with data for z < 0.5 in the framework of DE and alternative scenarios. Finally, the evolution of the average cosmic metallicity is presented and it shows a quite fast increase in each scenario, reaching the solar value at the present time, although most of the heavy elements are incorporated into solid grains, and therefore not observable in the gas phase.

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The Star Formation History of the Large Magellanic Cloud

Cited by 461 publications

References 69 publications

Planck2015 results

Planck2015 results

The morphology of the sub-giant branch and red clump reveal no sign of age spreads in intermediate-age clusters

The cosmic dust rate across the Universe

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