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Matt Brorby (U of Iowa) with Philip Kaaret (U of Iowa)

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Matt Brorby (U of Iowa) with Philip Kaaret (U of Iowa) Matt Brorby (U of Iowa) with Philip Kaaret (U of Iowa) Illustration: NASA/CXC/M.Weiss http://chandra.harvard.edu/ Outline • Why study ULX vs metallicity? • Observations: Einstein, ROSAT, etc: N"#$ ,�"#$ ∝ SFR • Recent studies: N"#$, �"#$ /SFR vs Metallicity • Does spectral state depend on metallicity? • How could metallicity affect ULX population? • Outlook for observable properties of ULX-metallicity effects Why? • Knowing the effects of metallicity on the properties of ULX will lead us to understanding more about the early Universe X-rays in the early Universe • Knowing the effects of metallicity on the properties of ULX will lead us to understanding more about the early Universe • Recombination • � ∼ 1000 • Dark Ages • 20 < � < 1000 • Reionization • 6 < � < 20 • Currently • Ionized and warm (IGM) X-rays in the early Universe • X-rays have a large mean free path, ; A.C � (cMpc) ∝ < 5 =>> ?@ (see McQuinn2012; Mesinger+2013; Pacucci+2014) • Allows for more uniform ionization • Most of X-ray energy is deposited as heat (left over energy after ionization) (Shull & van Steenberg 1985) • Would delay the end of reionization due to thermal feedback X-rays in the early Universe (Fialkov, Barkana, & Visbal 2014) • Fiducial model of X-ray emission D • < = 3×10K>� [erg sRS MRS yr] EFG $ ⊙ • � $ = 1 • Reduced X-ray emission S • �$ = S> Soft XRB spectrum • Enhanced X-ray emission Hard XRB spectrum • �$ = 10 • Minimum of curve is beginning of X- ray heating. (Fialkov, Barkana, & Visbal 2014) • Above �AS = 0, reionization begins. X-rays in the early Universe (MiroCha 2014) Gravitational Waves from BH-BH binary LIGO Scientific Collaboration and Virgo Collaboration (2016) • Initial black hole masses of XY XK 36RK M⊙ and 29RK M⊙ XK • Final mass of 62RK M⊙ • “The formation of such massive black holes from stellar evolution requires weak massive-star winds, which are possible in stellar environments with metallicity lower than ≈ 0.5 �⊙.” Abbott et al. (2016) (LIGO Scientific Collaboration and Virgo Collaboration) LIGO Collaboration (2016) LIGO Collaboration (2016) Detect Epoch of Reionization and earlier with next gen radio telescopes? Detectable by eLISA? ULX Correlation with star formation rate Number of ULX correlates with star formation Irwin, Bregman, Athey (2004) Liu, Bregman, Irwin (2006) =` L5 > 10 erg/s =` L5 > 1.6×10 erg/s Occurrence frequency (%) Star formation rate (M⊙/yr) ULX prefer dwarf galaxies Tremonti, et al. (2004) Galaxy Mass-Metallicity Relation Walton, Roberts, Mateos, Heard (2011) ⊙ M C 0 1 per $ # " N ULX specific frequency increases with decreasing host galaxy mass. Hint of metallicity at play? See also: Swartz, Soria, Tennant (2008) ULX prefer dwarf galaxies Tremonti, et al. (2004) Galaxy Mass-Metallicity Relation Walton, Roberts, Mateos, Heard (2011) ULX specific frequency increases with decreasing host galaxy mass. Hint of metallicity at play? See also: Swartz, Soria, Tennant (2008) Pakull & Mirioni (2002) ULX appear to prefer the more metal-poor dwarfs Pakull & Mirioni (2002) Mapelli et al. (2010): N"#$/SFR for sample of Prestwich et al. (2013): N"#$ for individual non-ellipticalgalaxies. SINGS galaxies, intermediate metallicity galaxies and the combined metal poor and extremelymetal-poor galaxies(XMPG). LoCal Proxies to Early Universe Galaxies • First galaxies are expected to be small in size and have very low metallicities. • Blue compact dwarf galaxy (BCD): • Intense, recent star formation (blue) • Small (∼ 1 kpc), irregular galaxy made up of clusters (compact) • Low mass (dwarf) dominated by gas mass IMAGE: Hubblesite.org Alessandra Aloisi and Marco Sirianni of STScI BCD: I Zwicky 18 Lyman Break Analogs Brorby, Kaaret, Mirabel, & Prestwich (2016) MNRAS, submitted • Large, gas-rich galaxies formed after the 912 Å 1216 Å first dwarf galaxies (hierarchical structure formation). • These early galaxies would have properties similar to those galaxies observed using the Lyman break technique (Lyman Break Galaxies). • Physical size, stellar mass, gas velocity dispersion, metallicity, SFR • Lyman break analogs (LBAs) display these qualities as well. (Heckman+2005; Hoopes+2007) • Best known local comparison to Lyman break galaxies (LBGs) • Local (� ≤ 0.2) Lyman Break Analogs Brorby, Kaaret, Mirabel, & Prestwich (2016) MNRAS, submitted • Large, gas-rich galaxies formed after the 912 Å 1216 Å first dwarf galaxies (hierarchical structure formation). • These early galaxies would have properties similar to those galaxies observed using the Lyman break technique (Lyman Break Galaxies). • Physical size, stellar mass, gas velocity dispersion, metallicity, SFR • Lyman break analogs (LBAs) display these qualities as well. (Heckman+2005; Hoopes+2007) • Best known local comparison to Lyman break galaxies (LBGs) • Local (� ≤ 0.2) ConClusions of BCD Study Brorby, Kaaret, & Prestwich (2014) • The XLF normalization for BCDs is � ∼ �⊙ enhanced by a factor of 9.7 ± 3.2 � ∼ 0.1 �⊙ compared to near-solar metallicity galaxies • Consistent with previous studies (Kaaret et al. 2011; Prestwich et al. 2013, Basu-Zych et al. 2013) • Fits in with predictions of X-ray binary formation in the early universe (Mirabel et al. 2011, Fragos et al. 2013) Mineo et al. (2012) Brorby et al. (2014); Mineo et al. (2012) LoCal Proxies to Early Universe Galaxies • Large, gas-rich galaxies formed after the 912 Å 1216 Å first dwarf galaxies (hierarchical structure Lyman break technique formation) with properties similar to those galaxies observed using the Lyman break technique (Lyman Break Galaxies). • Lyman break analogs (LBA) display these qualities as well. (Heckman+2005; Hoopes+2007) • Best known local comparison to Lyman break galaxies (LBGs): Physical size, stellar mass, gas Pettini (2003): Courtesy of Kurt Adelberger velocity dispersion, metallicity, SFR � of SF Galaxies 5 � Brorby, Kaaret, Mirabel, & Prestwich (2016) � g o l • Evidence for �5 − SFR − Metallicity Plane log SFR BCD (Brorby+2014) BCD Upper Limit Douna+2015 (Brorby+2014) Spiral/Irregulars (Mineo+2012) LBA (Brorby+2016) � = 0.34 dex 12 + log(Ο/H) �5 of SF Galaxies Brorby, Kaaret, Mirabel, & Prestwich (2016) • Evidence for �5 − SFR − Metallicity Plane BCD (Brorby+2014) BCD Upper Limit Douna+2015 (Brorby+2014) Spiral/Irregulars (Mineo+2012) LBA (Brorby+2016) ULX population and total X-ray luminosity are enhanced at lower metallicitiesin SF galaxies. Mapelli+2010 Prestwich+2013 Walton+2011 Do speCtral properties Change with metalliCity? =` • 71% of flux from sources with �5 ≥ 10 erg/s in HMXB population • Spectral shape of brightest X-ray sources has effect on heating of IGM in the early Universe (Kaaret 2014) Significant curvature in ULX spectra weakens the constraints from the soft X-ray background on the emission from early, bright HMXBs. z = 0 Γ = 2 Γ = 1.5, �w = 6.0 keV Γ = 0.8, �w = 2.1 keV z = 6 Kaaret (2014) SpeCtral Shape of X-ray Binaries • Low, hard state vs high, soft state I Zw 18 X-ray Spectra (Chandra & XMM-Newton) =` RS ULX • � ≤ 10 erg s K> 5 �5 = 1×10 erg/s =` �5 = 3.3×10 erg/s High flux, soft thermal emission Low flux, hard power law Kaaret & Feng (2013) VII Zw 403 X-ray Spectrum (Suzaku) Observations • Observed for 88.66 ks power-law fit • Spectrum is fit using a soft disc component and a hard Comptonizationcomponent. • Parameters: Disc temp: ��> = 0.09 keV - e coronal temp: ��{ = 2.2 keV � = 11.4 Coronal optical depth: Comptonization (compTT) K> RS • �5 = 1.7×10 erg s • Fully consistent with hard ultraluminous state Brorby et al. (2015) Suzaku Observations VII Zw 403 X-ray Spectrum (Suzaku) Brorby, Kaaret, & Feng (2015) • BCD: VII Zw 403 hosts ULX • Spectrum is fit using a soft disc component and a hard Comptonizationcomponent. • Parameters: Disc temp: ��> = 0.09 keV - e coronal temp: ��{ = 2.2 keV Coronal optical depth: � = 11.4 K> RS • �5 = 1.7×10 erg s • Fully consistent with hard ultraluminous state Brorby et al. (2015) Suzaku Observations VII Zw 403 X-ray Spectrum (Suzaku) Brorby, Kaaret, & Feng (2015) • BCD: VII Zw 403 hosts ULX • Spectrum is fit using a soft disc component and a hard Comptonizationcomponent. • Parameters: Disc temp: ��> = 0.09 keV - e coronal temp: ��{ = 2.2 keV Coronal optical depth: � = 11.4 K> RS • �5 = 1.7×10 erg s • Fully consistent with hard ultraluminous state Brorby et al. (2015) Sutton et al. (2013) I Zw 18 • Observed with Chandra and XMM- Newton • HST image in F675W band. • X marks dynamical center • + is location of X-ray source Brorby et al. (2015) Two BCD Galaxies Containing ULX ULX-like vs BHB-like I Zw 18 X-ray Spectra (Chandra & XMM-Newton) VII Zw 403 X-ray Spectrum (Suzaku) � = 0.019 �⊙ K> �5 = 1×10 erg/s � = 0.062 �⊙ High, soft state K> =` �5 = 1.7×10 erg/s �5 = 3.3×10 erg/s Hard, ultraluminous state Low, hard state Brorby et al. (2015) Kaaret & Feng (2013) Holmberg II & IX Two more low-Z galaxies Metalicity of ∼ 0.2 �⊙ (Egorovet al. 2013). � ∼ 0.4 �⊙ (Makarova et al. 2002) � = 0.1 �⊙ (Morales-Luis et al. 2011) X-1 + M81 X-1 DSS2 optical HEALPix survey, color (R=red[~0.6um]/G=average/B=blue[~0.4um]) GALEX:GII; NUV; PI:John Huchra Holmberg II & IX ULX-like speCtra Walton, Middleton, Rana, et al. (2015) Walton, Miller, Harrison, et al. (2013) Straight power law XMM-Newton (pn, MOS) NuSTAR (FPMA, FPMB) Suzaku (FI-XIS, BI-XIS) Cutoff power law Holmberg II X-1 � ∼ 0.2 � (Egorovet al. 2013). ⊙ Holmberg IX X-1 Suzaku � = 0.1 �⊙ (Morales-Luis et al. 2011) � ∼ 0.4 �⊙ (Makarova et al. 2002) Holmberg IX X-1 The ULX is located inside an association Part of a loose cluster of young stars. + M81 Holmberg II X-1 GALEX:GII; NUV; PI:John Huchra The ULX is located in a dense star-forming region of the galaxy which may indicate a dynamical center dynamically formed IMBH Brorby et al. (2015) Ott et al. (2005) Walton, Middleton, Rana, et al. (2015) Walton, Miller, Harrison, et al. (2013) Holmberg II X-1 Holmberg IX X-1 Straight power law XMM-Newton (pn, MOS) NuSTAR (FPMA, FPMB) Suzaku (FI-XIS, BI-XIS) Cutoff power law VII Zw 403 X-ray Spectrum (Suzaku) I Zw 18 X-ray Spectra (Chandra & XMM-Newton) IMBH candidate? Kaaret & Feng (2013) Brorby et al.
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