Bulge Asymmetries and Dynamic Evolution

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

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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

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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

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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

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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.