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Bulge Asymmetries and Dynamic Evolution
The BAaDE Project
Loránt Sjouwerman (NRAO) Mark Claussen (NRAO) Isaiah Santistevan (UNM) Michael Stroh (UNM) This material is supported by the National Science Foundation under Grant number 1517970
Michael Rich (UCLA) Mark Morris (UCLA) Cameron Trapp (UNM)
Ylva Pihlström (UNM)
TheBAaDEproject
Aim:TosignificantlyimprovemodelsofthedynamicsandstructureoftheGalac>cbulgeandtheinnerGalaxy.
• Usingradiodetectedpoint-massesprobingintoregionsnotreachablewith
op>calsurveys(-6<b°<6).
• Surveying~34,000starsforSiOmaseremissionusingVLAandALMA.– Directline-of-sightveloci>esobtainedfor20,000+stars
• UsingVLBAfordetailedorbitcharacteris>csinasubsampleofthesources.
Mainresearchgoals(A)
1. Galac>cdynamicsanddetailedGalac>cstructure– LOSveloci>es+loca>on=>globaldynamicalmodel– Velocityrota>oncurves&velocitydispersions(fordynamicalmodels)
– Instabili>esandasymmetries
– High-velocitystars,aretheyanen>repopula>oninfluencedbythebar?
2. Sta>s>csofSiOmasersintheGalaxy– Detec>onsta>s>csasfunc>onsofMSXcolor,Galac>cloca>onandvelocity
– Comparisonwith2MASS,GLIMPSE,WISE,AKARI,etc.– Correla>onbetweendifferentmasertransi>onsintheshell
OHandSiOmaserstars:IRASandMSX
• MasersinOH/IRstarshavepreviouslybeenusedforkinema>calstudiesoftheMilkyWay(e.g.,Habingetal.2006)– Only3000OHmaserstarsinMW
• IRAScolorspredic>veoffindingsourceswithcircumstellarmaterial.
• WorksalsoforMSX;incomparablecolorregionsthedetec>onrateofSiOmasersis50-90%.
VanderVeen&Habing1988Habing1996
Sjouwermanetal.2009,Messineoetal.2002.
TheBAaDEproject
VLAfrequencycoverage
ExampleVLAspectra:(v=1,2,3andisotope29SiOv=0)
ExampleVLAspectra:carbon
ExampleALMAspectra:Dual(v=1,v=2)
ad3a-03988 SPEC 3.NOIFS.1No calibration applied and no bandpass applied
Vector averaged cross-power spectrum Several baselines averaged
Mill
iAm
pl J
y
FREQ MHz85600 85800 86000 86200 86400 86600 86800 87000
500
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0 IF 1(I)
ad3a-04127 SPEC 4.NOIFS.1No calibration applied and no bandpass applied
Vector averaged cross-power spectrum Several baselines averagedM
illiA
mpl
Jy
FREQ MHz85600 85800 86000 86200 86400 86600 86800 87000
600
500
400
300
200
100
0 IF 1(I)
ExampleALMAspectra:Isotopes(29SiO),thermal
ad3a-04352 SPEC 5.NOIFS.1No calibration applied and no bandpass applied
Vector averaged cross-power spectrum Several baselines averaged
Am
pl J
y
FREQ MHz85600 85800 86000 86200 86400 86600 86800 87000
30
25
20
15
10
5
0 IF 1(I)
ad3a-04094 SPEC 4.NOIFS.1No calibration applied and no bandpass applied
Vector averaged cross-power spectrum Several baselines averaged
Am
pl J
y
FREQ MHz85600 85800 86000 86200 86400 86600 86800 87000
20
18
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10
8
6
4
2
0 IF 1(I)
Dameetal.(2001)
• COdistribu>onalongb=0°,andtheBAaDEfirstsetofdetec>ons.
• Differentpopula>ons.
• Noncircularmo>ons.
Aumer&Schönrich(2015)• Modelinginves>ga>ngthe“200km/sfeature”,tes>ngwithAPOGEEdata.
• Dynamicallycoolandyoungstarscapturedbythebar?
• Willbetestedbyobserva>onstonega>velongitudesandorbitaldetermina>onswiththeVLBA
3. VLBIpropermo>onsofGalac>corbitsandstructureofindividualstars– Propermo>onsandperhapsorbitfamily,andparallaxdistanceswhenpossible
4. SiOmasercharacteris>csandstellarandcircumstellarproper>es– SiOmaserstellarproper>eslikemagnitude,color,variability,distance,age,
metallicityifpossible,SEDs– Correla>onwithmaserintensity
Mainresearchgoals(B)
Summary
• Atthepointwherewearecollec>ngthebasicdata(VLA,ALMA)– SiOmasers/veloci>es– IRdata
• Preparingforfollow-upVLBAstudies– Calibratorsearches,pilotobserva>ons– Determiningsuitablesamples/keysources
• Firstdatarelease/paperearlySpring2016
• hqp://www.phys.unm.edu/~ylva/baade/
ThismaterialisbaseduponworksupportedbytheNaEonalScienceFoundaEonunderGrantNumber1517970.Anyopinions,findings,andconclusionsorrecommendaEonsexpressedinthismaterialarethoseoftheauthor(s)anddonotnecessarilyreflecttheviewsoftheNaEonalScienceFoundaEon.
