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LEGACY EXTRAGALACTIC UV SURVEY (LEGUS) WITH THE<i>HUBBLE SPACE TELESCOPE</i>. I. SURVEY DESCRIPTION
Calzetti, D.,Lee, J. C.,Sabbi, E.,Adamo, A.,Smith, L. J.,Andrews, J. E.,Ubeda, L.,Bright, S. N.,Thilker, D.,Aloisi, A.,Brown, T. M.,Chandar, R.,Christian, C.,Cignoni, M.,Clayton, G. C.,Silva, R. da,Mi IOP Publishing 2015 The Astronomical journal Vol.149 No.2
THE BRIGHTEST YOUNG STAR CLUSTERS IN NGC 5253
Calzetti, D.,Johnson, K. E.,Adamo, A.,Gallagher III, J. S.,Andrews, J. E.,Smith, L. J.,Clayton, G. C.,Lee, J. C.,Sabbi, E.,Ubeda, L.,Kim, H.,Ryon, J. E.,Thilker, D.,Bright, S. N.,Zackrisson, E.,Kennic IOP Publishing 2015 The Astrophysical journal Vol.811 No.2
<P>The nearby dwarf starburst galaxy NGC 5253 hosts a number of young, massive star clusters, the two youngest of which are centrally concentrated and surrounded by thermal radio emission (the 'radio nebula'). To investigate the role of these clusters in the starburst energetics, we combine new and archival Hubble Space Telescope images of NGC 5253 with wavelength coverage from 1500 angstrom 1.9 mu m in 13 filters. These include H alpha, P beta, and P alpha, and the imaging from the Hubble Treasury Program LEGUS (Legacy Extragalactic UV Survey). The extraordinarily well-sampled spectral energy distributions enable modeling with unprecedented accuracy the ages, masses, and extinctions of the nine optically brightest clusters (M-V < -8.8) and the two young radio nebula clusters. The clusters have ages similar to 1-15 Myr and masses similar to 1 x 10(4)-2.5 x 10(5) M-circle dot. The clusters' spatial location and ages indicate that star formation has become more concentrated toward the radio nebula over the last similar to 15 Myr. The most massive cluster is in the radio nebula; with a mass similar to 2.5 x 10(5) M-circle dot and an age similar to 1 Myr, it is 2-4 times less massive and younger than previously estimated. It is within a dust cloud with AV similar to 50 mag, and shows a clear near-IR excess, likely from hot dust. The second radio nebula cluster is also similar to 1 Myr old, confirming the extreme youth of the starburst region. These two clusters account for about half of the ionizing photon rate in the radio nebula, and will eventually supply about 2/3 of the mechanical energy in present-day shocks. Additional sources are required to supply the remaining ionizing radiation, and may include very massive stars.</P>
Stefano Calzetti,Anna Negrotti,Vladimiro Pietrini 대한파킨슨병및이상운동질환학회 2021 Journal Of Movement Disorders Vol.14 No.3
There is a long-standing debate regarding the comorbid association of Parkinson’s disease (PD) and restless legs syndrome (RLS) in the same patients. Recently, many studies have been focused mainly on the differentiation of the RLS cooccurring with PD from the primary form of the sensory-motor disorder [1], whereas possible heterogeneity in the pathomechanisms of RLS related to the timing of its onset in respect to the clinically overt PD and the so-called premotor/prodromal PD remains as yet unexplored.
Krumholz, Mark R.,Adamo, Angela,Fumagalli, Michele,Wofford, Aida,Calzetti, Daniela,Lee, Janice C.,Whitmore, Bradley C.,Bright, Stacey N.,Grasha, Kathryn,Gouliermis, Dimitrios A.,Kim, Hwihyun,Nair, Pre IOP Publishing 2015 The Astrophysical journal Vol.812 No.2
<P>We investigate a novel Bayesian analysis method, based on the Stochastically Lighting Up Galaxies (slug) code, to derive the masses, ages, and extinctions of star clusters from integrated light photometry. Unlike many analysis methods, slug correctly accounts for incomplete initial mass function (IMF) sampling, and returns full posterior probability distributions rather than simply probability maxima. We apply our technique to 621 visually confirmed clusters in two nearby galaxies, NGC 628 and NGC 7793, that are part of the Legacy Extragalactic UV Survey (LEGUS). LEGUS provides Hubble Space Telescope photometry in the NUV, U, B, V, and I bands. We analyze the sensitivity of the derived cluster properties to choices of prior probability distribution, evolutionary tracks, IMF, metallicity, treatment of nebular emission, and extinction curve. We find that slug's results for individual clusters are insensitive to most of these choices, but that the posterior probability distributions we derive are often quite broad, and sometimes multi-peaked and quite sensitive to the choice of priors. In contrast, the properties of the cluster population as a whole are relatively robust against all of these choices. We also compare our results from slug to those derived with a conventional non-stochastic fitting code, Yggdrasil. We show that slug's stochastic models are generally a better fit to the observations than the deterministic ones used by Yggdrasil. However, the overall properties of the cluster populations recovered by both codes are qualitatively similar.</P>
A WFC3 study of globular clusters in NGC 4150: an early‐type minor merger
Kaviraj, Sugata,Crockett, R. Mark,Whitmore, Bradley C.,Silk, Joseph,O’Connell, Robert W.,Windhorst, Rogier A.,Mutchler, Max,Rejkuba, Marina,Yi, Sukyoung,Frogel, Jay A.,Calzetti, Daniela Blackwell Publishing Ltd 2012 Monthly notices of the Royal Astronomical Society. Vol.422 No.1
<P><B>ABSTRACT</B></P><P>We combine near‐ultraviolet (NUV; 2250 Å) and optical (<I>U</I>, <I>B</I>, <I>V</I>, <I>I</I>) imaging from the Wide Field Camera 3 (WFC3), on‐board the <I>Hubble Space Telescope</I> (<I>HST</I>), to study the globular cluster (GC) population in NGC 4150, a sub‐L* (<I>M</I><SUB><I>B</I></SUB>∼−18.48 mag) early‐type minor‐merger remnant in the Coma I cloud. We use broad‐band NUV–optical photometry from the WFC3 to estimate individual ages, metallicities, masses and line‐of‐sight extinctions [<I>E</I>(<I>B</I>−<I>V</I>)] for 63 bright (<I>M</I><SUB><I>V</I></SUB> < −5 mag) GCs in this galaxy. In addition to a small GC population with ages greater than 10 Gyr, we find a dominant population of clusters with ages centred around 6 Gyr, consistent with the expected peak of stellar mass assembly in faint early types residing in low‐density environments. The old and intermediate‐age GCs in NGC 4150 are metal poor, with metallicities less than 0.1 Z<SUB>⊙</SUB>, and reside in regions of low extinction [<I>E</I>(<I>B</I>−<I>V</I>) < 0.05 mag]. We also find a population of young, metal‐rich (<I>Z</I> > 0.3 Z<SUB>⊙</SUB>) clusters that have formed within the last Gyr and reside in relatively dusty [<I>E</I>(<I>B</I>−<I>V</I>) > 0.3 mag] regions that are coincident with the part of the galaxy core that hosts significant recent star formation. Cluster disruption models (in which ∼80–90 per cent of objects younger than a few ×10<SUP>8</SUP> yr dissolve every dex in time) suggest that the bulk of these young clusters are a transient population.</P>