On the velocities that X-ray binaries receive at formation

Transcription

1 On the that receive at formation The effect of the Technion - Israel Institute of Technology with Andrei Igoshev & Gijs Nelemans (RU Nijmegen, NL) Binary Stars in Cambridge, July 28th, 2016, Technion The of s 1

2 , Technion The of s 2 (XRBs) XRBs contain a black hole (BH) or neutron star (NS) accreting mass from a stellar companion We focus on BH and NS-XRBs hosting a low-mass companion ( 1 M )

3 , Technion The of s 3 The of s The birth speeds of NSs are large ( 400 km/s; e.g. Hobbs ) NSs are born with natal Jonker & Nelemans 2004 measured same offset above the plane for s (z rms 0.7 kpc) BHs receive too? empty circles: NS-LMXB solid circles: BH-LMXB

4 , Technion The of s 4 kick on the kinematics V pec = V MLK M ej MBH M z What is the velocity at birth v_pec you need to bring the system at thatheightfrom the plane? V NK 2 + V MLK 2 2 M BH M V NK,x V MLK ; (M : total mass of the binary after the SN; V MLK : Blaauw kick; M ej : ejecta in the SN) current offset of the binary above plane delivers lower limit on peculiar velocity at birth V pec lower lim on natal kick R

5 The effect of the Why we are interested in BH The BH-BH merger rate goes down by 2 orders of magnitude if high BH (Dominik ; Belczynski, RS, ); observed BH merger rate cf. predicted rate high BH natal seem unlikely for BHs at high-mass end (see for example Belczynski and talk by Belczynski); high Belczynski affect the number of BHs which can be retained in globular and nuclear clusters (e.g. Morscher ; Antonini & Rasio 2016 );, Technion The of s 5

6 , Technion The of s 6 The physics of the Natal Kick Fryer & Kalogera+2011 Massive BHs form by direct collapse, light BHs via fallback onto the NS (Heger ; Fryer & Kalogera 2011 ) explosion energy vs BH progenitor mass

7 , Technion The of s 6 The physics of the Natal Kick Massive BHs form by direct collapse, light BHs via fallback onto the NS (Heger ; Fryer & Kalogera 2011 ) Fryer & Kalogera+2011 explosion energy vs BH progenitor mass In the asymmetric mass ejection kick mechanism, this results in BHs receiving reduced : V NK,BH = V NK,NS M NS /M BH reduced : few tens km/s full (high) : 100 km/s but, alternative mechanisms: ν-driven SN ejecta accelerating BHs to same velocity as NSs? (Janka 2013)

8 , Technion The of s 7 Natal : where do we stand Observational evidence: NS BH Low Kick High Kick (a few tens km/s) ( 100 km/s) double-ns systems 1 ; low ecc. Be X-ray binaries 2 small peculiar velocity of a few BH-XRBs 4 large proper motion of isolated pulsars 3 high peculiar velocity of a few BH-XRBs 5 1) Wong ; Beniamini & Piran ) Pfahl ) Hobbs ) Willems ; Wong ) Fragos

9 , Technion The of s 8 Minimal at birth of BH-XRBs: how to estimate them

10 , Technion The of s 9 Test of our analytical estimate V pec,min V pec,min = 2[ (R 0, z) (R 0, 0)] (RS, Davies & Sigurdsson 2012; RS & Nelemans 2015 ) Is this an accurate conservative estimate of the minimal initial velocity of the binary? (see Mandel 2016 ) Compare this estimate V pec with real velocity to reach a distance above the plane: z 2 > 1

11 , Technion The of s 9 Test of our analytical estimate V pec,min V pec,min = 2[ (R 0, z) (R 0, 0)] (RS, Davies & Sigurdsson 2012; RS & Nelemans 2015 ) Is this an accurate conservative estimate of the minimal initial velocity of the binary? (see Mandel 2016 ) Compare this estimate V pec with real velocity to reach a distance above the plane: z 2 > 1

12 , Technion The of s 9 Test of our analytical estimate V pec,min V pec,min = 2[ (R 0, z) (R 0, 0)] (RS, Davies & Sigurdsson 2012; RS & Nelemans 2015 ) Is this an accurate conservative estimate of the minimal initial velocity of the binary? (see Mandel 2016 ) Compare this estimate V pec with real velocity to reach a distance above the plane: z 2 > 1 Our analytical estimate is robust and can be used to estimate the initial velocity of XRBs Bulge sources are to be treated with caution: see poster 31 with Andrei Igoshev on a Bayesian approach to BH distances

13 , Technion The of s 10 approach for measuring BH

14 , Technion The of s 11 RS, Igoshev A., Nelemans G., 2016, under review (MNRAS) : - The of and its implications for compact object formation and -

15 , Technion The of s 11 RS, Igoshev A., Nelemans G., 2016, under review (MNRAS) : - The of and its implications for compact object formation and - Aims: Which imprints do different models for NS and BH formation have on the of containing them? Can we quantify these imprints? Which model for BH and NS formation (i.e. which natal kick) fits the observed best?

16 , Technion The of s 11 RS, Igoshev A., Nelemans G., 2016, under review (MNRAS) : - The of and its implications for compact object formation and - Aims: Which imprints do different models for NS and BH formation have on the of containing them? Can we quantify these imprints? Which model for BH and NS formation (i.e. which natal kick) fits the observed best? : Build synthetic populations of s, follow their binary evolution, and integrate their orbits ( binaries for each model)

17 2 types of natal kick: σ low = 40 km/s; σ high = 100 km/s Z rms [kpc] The scale height of XRBs BH, highnk, Mej=0 BH, low NK, Mej=0 NS highnk Mej=uniform NS, lownk, Mej=uniform BH, highnk, Mej=4 BH, lownk, Mej=0, MHe= R [kpc]. If BHs and NSs receive the same natal kick, they would still show a different scale height, with NSs reaching larger heights above the plane. Serena. Repetto, Technion The of s 12

18 The scale height of XRBs 2 types of natal kick: σ low = 40 km/s; σ high = 100 km/s BH, highnk, Mej=0 BH, low NK, Mej=0 NS highnk Mej=uniform NS, lownk, Mej=uniform BH, highnk, Mej=4 BH, lownk, Mej=0, MHe=15. If BHs and NSs receive the same natal kick, they would still show a different scale height, with NSs reaching larger heights above the plane. Serena. Repetto, Technion The of s 13

19 , Technion The of s 14 : BH-XRBs from BlackCAT of Corral-Santana

20 , Technion The of s 15 : a bias To measure the BH mass dynamically, high SNR spectra are required, which might be prevented in high-extinction region exclude from synthetic populations those binaries at z 0.1 kpc early - type stars late - type stars

21 , Technion The of s 16 : method We compare the (R, z) of synthetic binaries with the (R, z) of the obs. populations For every R-bin, we produce cumulative s (CDFs) of the z-values, and calculate at which position in the CDF the obs. binaries stand

22 , Technion The of s 17 : method We compare the (R, z) of synthetic binaries with the (R, z) of the obs. populations For every R-bin, we produce cumulative s (CDFs) of the z-values, and calculate at which position in the CDF the obs. binaries stand intersection between observed z-value and CDF of z-values in our simulations. then we make a cumulative of such intersections.

23 , Technion The of s 18 : Results 9 short-period confirmed high NK (100 km/s) low NK (40 km/s) Note: we exclude sources close to the bulge in this comparison 15 short+long confirmed high NK (100 km/s) low NK (40 km/s)

24 , Technion The of s 19 : Results 9 short-period confirmed KS-test results: high NK: D=0.26; p=0.57 low NK: D=0.34; p=0.24 Note: we exclude sources close to the bulge in this comparison 15 short+long confirmed KS-test results: high NK: D = 0.27; p=0.39 low NK: D = 0.35; p =0.14

25 , Technion The of s 20 The model in which (at least some) BHs receive a (relatively) high natal kick best fits the observed data.. But: sample is small false negative rate (FNR) still too high ( 30% for the low natal kick hypothesis). To decrease this rate to the level that in 95% of the cases we obtain a FNR less than 1% increase obs. sample to 40 systems

26 , Technion The of s 21 Effort in increasing number of BH-XRBs 1) A new BH candidate in the Galaxy At large offset from plane ( z 1 kpc) The Astrophysical Journal, 825:10 (13pp), 2016 July The American Astronomical Society. All rights reserved. doi: / x/825/1/10 THE FIRST LOW-MASS BLACK HOLE X-RAY BINARY IDENTIFIED IN QUIESCENCE OUTSIDE OF A GLOBULAR CLUSTER B. E. Tetarenko 1, A. Bahramian 1, R. M. Arnason 1,2, J. C. A. Miller-Jones 3, S. Repetto 4,5, C. O. Heinke 1, T. J. Maccarone 6, L. Chomiuk 7, G. R. Sivakoff 1, J. Strader 7, F. Kirsten 3, and W. Vlemmings 8 1 Department of Physics, University of Alberta, CCIS 4-181, Edmonton, AB T6G 2E1, Canada; btetaren@ualberta.ca 2 Department of Physics and Astronomy, University of Western Ontario, 1151 Richmond Street, London, ON N6A 3K7, Canada 3 International Centre for Radio Astronomy Research (ICRAR), Curtin University, GPO Box U1987, Perth, WA 6845, Australia 4 Physics Department, Technion Israel Institute of Technology, Haifa, 32000, Israel 5 Department of Astrophysics/IMAPP, Radboud University Nijmegen, PO Box 9010, NL-6500 GL Nijmegen, the Netherlands 6 Department of Physics, Texas Tech University, Box 41051, Lubbock, TX , USA 7 Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA 8 Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE Onsala, Sweden Received 2016 March 10; revised 2016 April 28; accepted 2016 May 1; published 2016 June 27

27 , Technion The of s 22 Effort in increasing number of BH-XRBs 2) A possible BH candidate discovered in the Bulge Survey (Jonker ): Follow-up of the Bulge Survey source CX1004: a candidate Black Hole X-ray Binary ; RS , to be submitted

28 , Technion The of s 23 : Our population shows that different CO formation models have an imprint on the of s; We quantify these imprints in terms of the scale height above the plane, z rms ; NS-XRBs have a larger z rms. than BH-XRBs; The simulated population in which at least some BHs receive a (relatively) high natal kick ( 100 km/s) fits the data best (in agreement with RS, Davies & Sigurdsson 2012); Our analytical estimate V pec,min is robust and can be used to estimate the peculiar velocity at birth of BH-XRBs.

29 , Technion The of s 24 Back-up slides

30 , Technion The of s 25 Bias towards low Observed systems are within 10 kpc from the Sun Check for possible observational biases that make that the observed systems are predominantly those with particular NK

31 Bias towards low Synthetic population of BH-LMXBs such that RLO within MS lifetime Integrate orbits in Galaxy and check which systems within 10 kpc from the Sun like the obs. systems 10 9 M D Technion The of s 26

32 Models for BH and NS formation Two types of natal kick: σ M x. = 40 km/s (low) or σ M x. = 100 km/s (high) BH Model 1: high NK, M ej = 0 (M BH = 8 M ); Model 2: low NK, M ej = 0 (M BH = 8 M ); Model 3: high NK, M ej = 4 (M BH = 8 M ); Model 4: low NK, M He = 15 M, M ej = 0 (M BH = 15 M ). NS (M NS = 1.4 M ): Model 5: high NK, M ej in [1.4, 6.6] M ; Model 6: low NK, M ej in [1.4, 6.6] M. Motivations: M ZAMS = [25, 60] M M He = [8, 11] M (Belczynski ) M ej in the NS case motivated by typical Helium-core mass of [2.8 8] M (Tauris & van den Heuvel 2006 ), Technion The of s 27

33 , Technion The of s 28 : NS-XRBs

34 , Technion The of s 29 2) Standard systems Low peculiar velocity could be due to MLK

35 , Technion The of s 30 Prob for bound orbit & systemic velocity

36 , Technion The of s 31 Distribution of V pec PDF V

37 , Technion The of s 32 Parameter space presn and V pec