Intro Talk ISM*@ST

Transcript

1. Intro talk
 ISM*@ST Caroline BOT rasbourg
2. Tignes, Alps Mt St Odile, Vosges
3. danced conference with Buto dancer Shoichi Fukushi text for the Opera House for Calisto having fun with birthday cakes but also visiting museums, sewing, …. porcelain painting
4. 50% 17% 33% • adjunct-astronomer position • my research: dust emission in nearby galaxies • It all started with a PhD thesis project for J. Chastenet
 2014: 5 months visit at STScI
 worked with Karl & Julia
 then Heddy Arab 
 then Katharina Lutz Why do I connect to this group every week? research service tasks teaching
5. HI emission (Bruens et al. 2005) 500!m dust emission (HERITAGE) Research interests: • dust emission in nearby galaxies • foreground/background emission • archival data sets • using Hierarchical Progressive Surveys (HiPS) for data analysis Magellanic Clouds
6. Dust emission in the Magellanic Clouds dust emission as a tracer of dust properties • Bot et al. 2004: ISO data: dust in the diffuse medium of the SMC • Gordon, Bot et al. 2009: Spitzer: dust abundance in Magellanic tail • Gordon, Roman-Duval, Bot et al. 2014: the Magellanic Clouds SEDs with Spitzer+Herschel are better fit at long wavelengths with a broken-emissivity modified black body • Roman-Duval, Gordon, Meixner, Bot et al. 2014: variations of the gas-to-dust variations in the Magellanic Clouds • Roman-Duval, Bot, Chastenet, Gordon 2017: stacked SEDs of IRAS+Planck in gas density bins -> the gas/dust decreases between the diffuse and the dense ISM of the Magellanic Clouds IR SED Mdust dust model Mgas gas to dust ratio metallicity does it scale? - dust growth - dust destruction + other dust prop. Mgas/Mdust=1200+1600-420 Roman-Duval et al. 2014, SMC
7. • Study the dust properties in each point of the Magellanic Clouds, using Spitzer+Herschel data and trying different dust models in a consistent way
 -> how do dust properties change?
 • from Gordon et al. 2014
 • 2 full dust models: THEMIS + Compiègne et al. (2011)
 different environment settings: single ISRF, multi-ISRF 
 + change the grain size distribution Brute Force Fitter different dust models, different results Jeremy Chastenet’s thesis, co-direction with K. Gordon
8. • THEMIS model reproduces the shape of the IR SEDs better • dust abundances depend on modeling choices
 
 
 
 • lower silicon to carbon dust ratio than in the MW Mdust depends on the dust model used and on the choices in the modeling Chastenet, Bot, Gordon et al. (2017)
9. Future: better understanding dust opacity is one key part for better anchoring dust properties • pure-parallel, multi-headed attack on dust evolution and star formation in ULLYSES galaxies • By comparing AV from the BEAST with AV from IR emission, we will have direct access to the opacity and emissivity of dust scare-plot from C. Clark SCYLLA 
 P.I. C. Murray
10. The long-wavelength shape of dust emission another lack in our understanding of the dust SED in galaxies • Israel et al. (2010), Bot et al. (2010): discovery of an excess mm-cm emission in the Magellanic Clouds, above dust, free-free and synchrotron • Planck collaboration (2011): excess in LMC explained by positive CMB fluctuation + cirrus foreground emission. 
 Significant excess remains unexplained in SMC • Cold dust ruled out (needs to be ~3K), solid state-effects or spinning grains possible (but difficult),magnetic dipole from magnetic nanoparticles (Draine & Hensley 2012)
11. Future: microwave emission of nearby galaxies • Is there still an excess of emission in the SMC 
 when using latest Planck data release • + recent dust model like THEMIS
 contains large amorphous C grains with flatter (sub-)mm emissivity • use to constrain better degeneracies/uncertainties • preliminary result: THEMIS model seems to be able to reproduce the full SED in the SMC • but also needs to have SMC on a positive CMB fluctuation
 Issue: Planck collaboration (2015) studied M31: also on a positive CMB fluctuation (and LMC as well)… unlikely! Brute Force Fitter Project 1: redoing the Magellanic Clouds Katharina Lutz
12. Future: microwave emission of nearby galaxies • What are the mm-cm properties of nearby galaxies? • same setting (THEMIS + ) • study the dust properties of nearby galaxies at long wavelengths in a consistent way • how often do we see a mm-cm excess? how flat is the SED? how many times do galaxy sit on positive CMB fluctuations? • include all the IMEGIN galaxies that will be observed with NIKA2 (P.I. S. Madden) to compare the low resolution dust properties to high resolution observations (but limited to bright regions) -> hints at diffuse dust emission Brute Force Project 2: looking at all IRAS+Planck detected nearby galaxies Axel RYMAR
 (Master 2 student) Katharina Lutz Roberta Paladini
13. very very first results: Importance of foreground cirrus emission and background (CIB, CMB fluctuations)
14. • unresolved/resolved stellar light • zodiacal light • Milky Way cirrus • unresolved background galaxies (CIB) • Cosmic Microwave Background • Free-free & synchrotron emission from field sources credit: Planck Foreground and background for low luminosity galaxies, we need to care about possible contaminants to dust emission λ
15. IRIS-DIRBE comparison or the still-in-prep. paper (but I will not resign! it will be published) • IRAS 100µm data is one of the most widely data set used in IR SEDs • Latest version is called IRIS and was calibrated on DIRBE (Miville-Deschenes & Lagache 2005) • Large scale comparison of DIRBE and IRIS at 100µm shows global agreement but significantly biased regions (Bot et al., still in prep.) Magellanic Clouds!
16. IRIS-DIRBE comparison • found an error on the DIRBE beam used previously • systematic bias uncovered between 2 data releases (|β|> or < 50o) • improvements on convolution kernels, edges of maps, use of healpix allsky format,… • Missing step in processing • New map: significant improvement 
 of the whole sky photometry
17. Future: Using HiPS for data analysis • HiPS = Hierarchical Progressive Survey 
 (Fernique et al. 2015) • based on Healpix tessellation of the sky
 hierarchical properties for computation • structure in suit of individual files 
 -> suited to much higher resolutions • >800 image data sets in HiPS • goal: do analysis in HiPS directly • 1st step: quantifying the uncertainty in the photometry introduced by the projection • Analyse flux correlations between maps at different wavelengths, using regions defined by Multi-Order Coverages (MOC) (e.g. different E(B-V) thresholds, or NHI thresholds, … for cirrus) Alex Hubert 
 M1 student
18. Scientific interest, ongoing projects and future • I am interested in dust in nearby galaxies, their foreground and background emission and image data sets especially archival ones • Ongoing projects: • collaboration on Scylla for better dust opacity constraints • Microwave dust emission of nearby galaxies: 
 dust properties, mm-cm excess emission, CMB 
 fluctuations as a background • IRIS-DIRBE paper: to be published • Using HiPS specificities for new science • Looking forward to other opportunities, collaborations 
 and new rabbit holes to fall into