Resolving the fine structure of the Galactic interstellar medium with

ATCA HI 21cm measurements L. Viktor Tóth (Eötvös University, & Konkoly Obs. Budapest)

Collaborators:L.G.Balázs,Zs.Bagoly,M.Cunningham,H.Dénes,Y.Doi,J.Hakkila,I.Horvath,T.Kovács,P.Jones,

T.Onishi,S.Pintér,I.Rácz,S.Zahorecz

The1.7GpcGRBRingatz=0.8(Balázs+2015MNRAS)

Motivation and consequences

• Motivation:foregroundofextragalacticsources•  Specialmotivation:GRB• Variousallskysurveysandtheiruse• HIwithATCA• Dénes,Jones,Tóth,Zahoreczetal.2018tobesubmitted

Speaking of Science

The new biggest thing in the universe, and why it’s a headache for scientists By Robert Gebelhoff August 20, 2015

The1.7GpcGRBRingatz=0.8(Balázs+2015MNRAS)

•  redshiftrange:0.78<z<0.86•  21GRBs(overdensityinzdistribution)•  ringof9:meanangulardiameterof36deg•  correspondingto1720Mpcinthecomovingframe•  coordinatedstarformingactivityamongtheresponsibleGRBhosts?

The 1.7 Gpc GRB Ring at z=0.8 (Balázs+ 2015 MNRAS)

AGWeventannouncedonMonday16thOct.2017Multi-messengerObservationsofaBinaryNeutronStarMerger

(LIGOS.C.,VirgoC.,FermiGBM+2017ApJ)GravitationalWavesandGamma-RaysfromaBinaryNeutron

StarMerger:GW170817andGRB170817A(LIGOS.C.,VirgoC.,FermiGBM+2017ApJ)

AnOrdinaryShortGamma-RayBurstwithExtraordinaryImplications:Fermi-GBMDetectionofGRB170817A

(Goldstein,A.;Veres,P.+2017ApJ)…

andalotofotherpapers

GRBs in the headlines again What happened on 17 Aug. 2017?

What happened on 17 Aug. 2017? •  Agravitationalwaveevent(laterdesignatedGW170817)wasobservedat12:41:04UTCthroughbytheAdvancedLIGOandAdvancedVirgodetectors.

•  TheFermiGamma-rayBurstMonitorindependentlydetectedagamma-rayburst(GRB170817A)withatimedelayof~1.7swithrespecttoGW170817.Fromthegravitational-wavesignal,thesourcewasinitiallylocalizedtoaskyregionof31deg2ataluminositydistanceof40±8Mpcandwithcomponentmassesconsistentwithneutronstars.

•  Thecomponentmasseswerelatermeasuredtobeintherange0.86to2.26M¤.•  Anobservingcampaignwaslaunchedacrosstheelectromagneticspectrumleadingtothediscoveryofabrightopticaltransient(SSS17a,nowwiththeIAUidentificationofAT2017gfo)inNGC4993(at~40Mpc)lessthan11hoursafterthemergerbytheOne-Meter,TwoHemisphere(1M2H)teamusingthe1mSwopeTelescope.

•  Theopticaltransientwasindependentlydetectedbymultipleteamswithinanhour.Subsequentobservationstargetedtheobjectanditsenvironment.

•  Earlyultravioletobservationsrevealedabluetransientthatfadedwithin48hours.•  Opticalandinfraredobservationsshowedaredwardevolutionover∼10days.•  Followingearlynon-detections,X-rayandradioemissionwerediscoveredatthetransient’sposition~9and~16days,respectively,afterthemerger.BoththeX-rayandradioemissionlikelyarisefromaphysicalprocessthatisdistinctfromtheonethatgeneratestheUV/optical/near-infraredemission.

•  Noultra-high-energygamma-raysandnoneutrinocandidatesconsistentwiththesourcewerefoundinfollow-upsearches.

àGW170817wasproducedbythemergeroftwoneutronstarsinNGC4993followedbyashortgamma-rayburst(GRB170817A)andakilonova/macronovapoweredbytheradioactivedecayofr-processnucleisynthesizedintheejecta.

GRB 170817A and

GW170817

•  Gamma-rayburstsasdetectedbytheFermi(2bands)andINTEGRAL(1band)satellites

•  GravitationalwaveeventdetectedbyLIGO-HanfordandLIGO-Livingstondetectors

•  Resultedbyabinaryneutronstarmerger

Abbot+2017ApJ

Localization of the gravitational-wave (from the LIGO-Virgo 3-detector global network), gamma-ray (by the Fermi and INTEGRAL satellites) and optical (the Swope discovery image) signals

http://public.virgo-gw.eu/ligo-and-virgo-make-first-detection-of-gravitational-waves-produced-by-colliding-neutron-stars/

AlenticulargalaxyLocationoftheGWsourcemarkedHSTimagehttps://apod.nasa.gov/apod/ap171023.htmlImageCredit:NASA&ESA

NGC 4993 the host galaxy

GW170817 afterglow

Multibandobservationshttps://kilonova.space/kne/GW170817/

Gamma-ray bursts (GRB) – as they appear

•  briefeventsoccurringatanaveragerateofafewperday•  Typicallyforabriefperiodofsecondstominutes•  Onanotherwisealmostdarkgamma-raysky•  Whiletheyareon,theyoutshineeveryothersourceofgamma-raysinthesky,includingtheSun.

•  TheyarethemostconcentratedandbrightestelectromagneticexplosionsintheUniverse.

•  GRBswerefirstdiscoveredin1967bytheVelasatellites,althoughtheywerenotpubliclyannounceduntil1973[224].Thesespacecraft,carryingomnidirectionalgamma-raydetectors,wereflownbytheU.S.DepartmentofDefensetomonitorfornuclearexplosionswhichmightviolatetheNuclearTestBanTreaty.

GRB170817AintheFermiduration-hardnessplane

(Goldstein,Veres+2017ApJ)

T90=2.048sHR32=0.56

Short,hardtype

Long,softtype

•  classifiedaccordingtothelengthoftheirγ–rayemission:T90

•  Mainclassesare: long&short

•  Gammaspectralhardnessisdefined(spectralindex)

•  Shortburstare„hard”•  Longburstsare„soft”Itisanoutdatedclassification

Classification of GRBs

duration-hardnessplane

Long or “classical” GRBs (Mészáros 2006)

•  associatedwithexplosionsofmassivestars(Stanek+2003)•  expectedtotraceongoingstar-formationuptoz=9.4•  Promptγ-rayemission(0.1-2MeV)–internalshock

•  Thermalemissionfromthephotosphere•  Non-thermalemission,producedinthejet•  byreverseshockpropagatingbackintotheejecta•  Note:Lesslikelyfrommagneticreconnectionordissipationprocesses,iftheejectaishighlymagnetized

•  Afterglow–externalshock•  fireballadvancingintoanapproximatelysmoothexternalenvironment(windblownstellarorISM)

•  GRBjetimpactsthesurroundingmediumàafterglow(e.g.Mészáros+Rees1992;Sari+1998)

Long GRB fireball model (Mészáros 2006)

LGRBs – information on distant stars, and IGM

•  Explosionofanindividualstarvisiblefromz>7•  Observedradiationcarriesinformationabout

•  GRBprogenitor•  ISMaroundGRBinitshostgalaxy•  mediaalongpath

Firststars firstquasars nowAgeoftheUniverse 500Myr 3Gyr 6Gyr 13.7Gyr

Intrinsic ISM parameters (density, metallicity, …) at the GRB jet (< 200 pc)?

• WhataretheparameterstherearoundtheGRB?•  Afterglow:continuumradiationinallwavelengths•  AfterglowX-rayspectrum–brightand“simple”

•  Approximatedaspower-lawcontinuummodulatedbyabsorption(Behar+2011;Schady+2011;Zafar+2011;Campana+2012…)

•  Ironemissionline

•  Absorption:intrinsic,CGM,IGM,MW (eg.Schady2015JHEA)

•  RestframeopticalandUVabs.lines(eg.Fynbo+2009gas;Elíasdóttir+2009dust;Perley+2011,

Schady+2011)•  Metallicityandextictionpeculiarities

GRB 070802 Lα spectral line (Elíasdóttir+ 2009)

Estimating the Galactic foreground – input data

SwiftGRBsatlowBwithknownzoverlaidonN(H)map(LAB)

•  Spectroscopy•  HIsurveys

•  LAB36’(LeidenArgentineBonnSurvey,Bajaja+1985;Kalberla+2005)

•  EBHIS10.8’(Effelsberg-BonnHISurveyofMilkyWaygasWinkel+2015)

•  HI4PI16.2’(EBHIS+GASS,HI4PIcollaboration2016)

•  IRASproducts5’-6’•  SFD(IRASrecalibrated,Schlegel+1998)•  SFDrecalibrated(SDSS,Schlafly+2011)

New:•  pan-STARRS1E(B-V)7’-14’(d<4.5kpcstellar

photometry,Schlafly+2014,Green+2015)•  AKARIFIS2’(Doi+2015)•  PlanckPR2AV5’Planck,IRAS,WISE

intermediateresultsXXIX(PlanckCollab.2016)

Estimating the intrinsic N(H) – LAB foreground

SwiftGRBsatlowBwithknownredshiftoverlaidonN(H)map(LAB)

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+06

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41e

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b [°]

NH

host

(LAB

) [cm

−2]

•  IntrinsicN(H)fromXspecX-rayafterglowspectralfit•  GalacticforegroundestimationisbasedonLAB(36’)•  ànoISMatGRBforasubsample?

àNO!

ToolowintrinsicN(H)forvariousdirections

IRASbasedN(H)Schlegeletal.1998

HI21cmlineintensityWinkeletal.2016

HI21cmlineintensityDickey&Lockmann1990

PlanckbasedN(H)Tóth+2017

AKARIbasedsmoothedN(H)Tóth+2017

AKARIbasedN(H)Tóth+2017

GRB131227A,z=5.3;foregroundN(H)20%lower

About 400 SWIFT detected GRB sources with known spectroscopic redshifts. Selected 84:

-availablegoodqualityAKARIFISimages-bestX-rayafterglowlightcurves-bestX-rayafterglowspectra

Lowandintermediategalacticlatitudesareover-represented

B

L

z

Estimating the Galactic foreground – data processing

PlanckAVPR2-  basedonWISE12μm;IRAS60μm

&100μm;Planck857GHz;545GHz;353GHzPR2

-  Dustmodel(Drain+Li2007)renormalizedtoSDSSQSO

AKARIFISbasedN(H)-  AKARIFarInfraredSurveyor(FIS,

Kawada+2007)-  Allskyimages65,90,140,

160μm(Doi+2015)-  Zodisubtraction(Ootsubo+2016)-  T_dustàradianceàN(H)-  Smoothedto5’&correlatedwith

PlanckAV-  30’x30’fieldsselected(GRBs)-  RenormalizedtoPlanck

CorrelationofPlanck&AKARIbasedN(H)

Planckmaps:http://pla.esac.esa.int/pla/#maps

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NHgal Akari (5’ res) [1e22 cm−2]

NH

gal

from

Pla

nck

[1e2

2 cm

−2]

GRB 051022A – an LGRB in the Giant GRB Ring

•  WellknowndarkLGRB,(noopticalafterglowßAV,Int)•  Hostgalaxy

SFR=271M⊙yr-1(from[OII]lineflux);stellarmass:logM*=10.42±0.05M⊙(Levesque+2014);detectedinCO4-3(ALMA,Hatsukade+2014)

•  HIforegroundEBHIS:N(H)Gal=3.9E+20cm-2

Planck smoothedAKARIFIS AKARIFIS AKARI:N(H)Gal=3.3E+20cm-2(Tóth+2017)

X-ray spectrum of GRB 051022A re-fitted

•  Swift-XRTGRBCatalogue(Evans+2009)

•  analyzedwithXspec(Arnaud1996)

•  samemodelasintheautomaticanalysisoftheUKSSDC(Evans+2009)

•  withrefinedAKARIbasedforegroundN(H)Gal

•  N(H)Intathostgalaxy:5%higher 10.5 2 5

10−3

0.01

0.1

norm

aliz

ed c

ount

s s−

1 keV

−1

Energy (keV)

GRB051022

N(H) from LABN(H) from AkariN(H) from EBHISN(H) from Planck

Seealso:http://www.swift.ac.uk/xrt_spectra/docs.phphttp://www.swift.ac.uk/xrt_spectra/algorithm.php Rácz+2017

ATCA HI 21cm observations

• Observations•  2015-2016-2017,alsousing“greentime”

•  4targets•  LGRBswithspectroz;precisepositions•  strongX-rayafterglow;highS/NX-rayspectra•  galacticforeground:2x1020cm-2<N(H)LAB<8x1020cm-2

•  Severalarrayconfigurations•  2-3arcminutesresolution

• Goodspectralresolution•  0.1km/s

GRB100425 L=14.8; B=-25.3

GRB070508 L=314.9; B=-32.4 –– near Cha

ATCA HI 21cm observations

•  ReductionwithMiriad•  Calibrated•  CombinedwithParkesGASSsurveydata

•  lowresolution16’•  binnedchannels1km/s

•  Correctedforbeam•  ConvertedtoTB[K]•  Continuumsources•  Absorptionsearched

Dénes,Jones,Tóth,Zahorecz+inprep.

Galactic foreground - ATCA HI 21cm with optical depth correction using continuum point sources

•  Spatialresolution:2.75’x2.12’•  velocityresolution:0.103kms-1

•  onephaseISM

•  i.e.themeasuredTBwascorrectedwiththeopticaldepthfromHIabsorptiontowardsacontinuumsourcenearthetarget

•  GRB081008(seeontheright)

Dénes,Jones,Tóth,Zahorecz+inprep.

HI 21cm line, τ, corrected line

• NearChaclouds• HIspectrumcorrectedforopticaldepth

• DerivedHcolumndensityincreasedby50%

Dénes,Jones,Tóth,Zahorecz+inprep.

•  a

HI4PI & ATCA HI foreground

X-ray afterglow spectrum of GRB 070508 re-fitted using ATCA HI foreground

•  Swift-XRTGRBCatalogue(Evans+2009)

•  analyzedwithXspec(Arnaud1996)

•  samemodelasintheautomaticanalysisoftheUKSSDC(Evans+2009)

•  N(H)Gal•  HI4PI:7.1x1020cm-2

•  RQ:10.3x1020cm-2

•  ATCA:14.6(9.0)x1020cm-2

•  HostgalaxyN(H)Int:few%diff.

SeealsoRácz+2017;Tóth+2018Dénes,Jones,Tóth,Zahorecz+inprep.

Resolution dependence of the Galactic foreground (MW) hydrogen column density

Tóth+2017

AKARIandLAB PlanckPR2andAKARI

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NHgal LAB [1e22 cm−2]

NH

gal A

kari

[1e2

2 cm

−2]

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NHgal Akari [1e22 cm−2]

NH

gal

from

Pla

nck

[1e2

2 cm

−2]

Effect of foreground (MW) correction on the intrinsic (host galaxy) hydrogen column density

Tóth+2017

Galacticforeground(MW) IntrinsicN(H)(hostgalaxy)

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NH

gal A

kari

[1e2

2 cm

−2]

Summary

•  GRBs•  Galacticforegroundrevealedby

•  PlanckandHIsurveys•  N(H)MWoftenslightlylowerthanLABestimates

•  ClumpyISM(alsoatlowcolumndensities)

•  Resolutionmatters(abit)•  higherintrinsicN(H)atsomecases •  NeedfurtherhighresolutionN(H)

Planck PR2 RQ AV centered to the double core (Daniel’s talk, Zahorecz+ 2018)

HI4PI N(HI) centered to the double core (Daniel’s talk, Zahorecz+ 2018)

Galactic foreground - Osaka-1.85m CO (2-1)

Onishi+2017priv.comm.

Spatialresolution:2’velocityresolution:0.1kms-1