# Ay215: A Seminar Course on Stellar Black Holes

Presentations/"Ay215.html Ay 215 - Team C.pdf" Presentations/"Ay215 - Team D.pdf Brochure_Ay215.pdf" Brochure
1. Class: 6 January 2020: Kulkarni talk |  Kasliwal Talk  |  Ozel+(2010) paper which served as background for SRK talk.
At the next class we will discuss paper by Elbert, Bullock & Kaplinghat (2018).

2. Class: 11 January 2020: Pedagogical Intro Team A (Dong, Somalwar, Sharma, De) presented their report on the Elbert at al. (2018) paper.
For next session we will discuss Thompson et al. (2019) & Rebuttal
For (eager) (Caltech) beavers: Jayasinghe et al. (2020)

3. Class: 13 January 2020:
1. List the features (distance, features, discovery year) of the nearest members of the degenerate class (brown dwarfs, white dwarfs, neutron stars, black holes).
2. Give a volumetric rate, n_*, derive the probability function of finding the nearest member at distance 4.
3. Redo the above problem but for two members.

Team B presented the Thompson et al. (2019) paper & rebuttal papers.

4. 18 January 2020: MLK Holiday

5. Class: 20 January 2020:
1. Exercise DZD: . Assume a Salpeter IMF (n=1.3) for the Milky Way galaxy, for the last 10 billion years. Compute the number of white dwarfs, neutron stars (8<M<20 solar masses) and black holes (M>20 solar masses). Compute the local density of the remnants. [Caution: think carefully about velocity kicks imparted at the births of the compact objects].
2. Exercise BB: Consider a system like the one described by Thompson et al. (2019). Assume that the eccentricity of the binary is 0.1. Estimate the time it will take to reduce thsi eccentricity to, say, 0.01. [Read up and, should all fail, consult local expert Jim Fuller]
3. Exercise IC: The parallax to the purported black-hole binary is an important physical parameter in the analysis of the Thompson et al. (2019) paper. That paper used the parallax given in Gaia DR2 of 0.271 mas with an uncertainty of 0.049 mas. Check out (i.e. verify me out) that the parallax in EDR3 is 0.400 mas with an uncertainty of 0.016 mas. The distance, assuming an underlying Gaussian distibution, is 2.5 kpc (and ranging from 2.4—2.6 kpc at 1-sigma and 2.3—2.8 kpc at 2.5-sigma). What are the consequences to the Thompson et al. paper given these revised parallaxes?
4. Exercise SRK (optional): Formally the measured parallax cannot be less than zero. Thus the distribution of the error of the parallax cannot be Gaussian (especially if the SNR of the measurement is modest). Compute the distance to the putative black hole system using sensible approximation (i.e. parallax must be >0).
References: Igoshev, Verbunt & Cator (2016)  |  Bailer-Jones (2015)

Nota bene: The exercises are named in honor of the participants in the class.

Team C reviewed the "GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object" .
Teams reformed. Team A: Jean, Viraj, Dillon. Team B: Bryce, Nitika, Kishalay. Team C: Yoonsoo, Shreya, Ilaria.

6. Class: 25 January 2020: All members are expected to read up "On the formation of GW190814" by Lu, Beniamini &Bonnerot (2020). The class will begin with a 45-minute presentation of the paper by Wenbin Lu and the remaining 45 minutes will be for Q&A.   Presentation by team C.
Problems for next class:
1. SRK: Orbital evolution of planetary system of a 3 Msun star: Assume that a 3-Msun star has a solar system identical to our own system. The star evolves and expands and eventually shrinks to a white dwarf. Ignoring planet-planet interactions work out the planetary system at the time the star is a hot white dwarf.
2. DZD: Orbital evolution due to mass transfer. Two stars of mass M1 and M2 are going around each other with orbital period, P and separation a. Assume that star 1 has filled its Roche lobe. Assume that mass is transferred from star M1 to M2. Further, assume mass and angular momentum conservation (i.e. mass and angular momentum lost by star 1 is full captured by star 2). Work out the evolution of the orbital separation.
3. MMK: Angular Momentum Loss . Redo the above problem but assume there is a loss of angular momentum (e.g. due to graviational wave radiation). Work out an expressionf or (da/dt)/a in terms of (dM1/dt)/M1 and (dJ/dt)/J.

7. Class: 27 January: Team A to review the "Pulsational Pair-instability Supernovae" by S. E. Woosley.
Presentation by Team A.

8. Class: February 1: Team B to review "Properties and Astrophysical Implications of the 150 M ⊙ Binary Black Hole Merger GW190521" by LVC.
Presentation

9. Class: February 3: Note: class is 3:30-5p Team C to review "Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g*"
Presentation. Graham will be attending the class.
New Teams: Team A: Jean, Ilaria; Team B: Bryce, Kishalay; Team C: Yoonsoo, Viraj; Team D: Nitika, Dillon

10. Class: February 8: LMXB Black Holes: Phenomena
Team A to review the paper by McClintock & Remillard  |  Presentation
See Tauris & van den Heuvel for a wonderful review of the astrophysics of binary star scenarios.

11. Class: February 10: Stellar Black Holes: An observer's view
Team B to review paper by Mirabel  |  Presentation
Homework problems (for next class): [1] What is the age of observed LMBH systems? [2] What are the revised Gaia space motions, [3] What is the contribution of Galactic heating to the space motion of LMBH systems?

12. February 15 (holiday)

13. Class: February 17: Microlensing searches for black holes
Team C to review Black hole, neutron star and white dwarf candidates from microlensing with OGLE-III. Mroz will be attending the class.
Presentation by Kim & Karambelkar
Homework Problem: [YN] Consider a red-clump star in the bulge (8kpc) and a solar mass star at 1 kpc. Magnification is 10. At what angular separation can you resolve this asterism with Keck AO? with ESO Gravity? You should also consider shift of photo-centroid of the asterism. [KDE] What is the sensitivity of the parallax effect with respect to the direction of the lens (ecliptic latitude)?

14. Class: February 22: Black holes in globular clusters-I Team D to present Rodriguez, Chatterjee & Rasio. Extra-reading (a cautionary tale) Kulkarni, McMillan & Hut. Rodriguez & Kulkarni will be attending the class.
Presentation by NY & DZD
New configurations for teams: Team A: Jean, Yoonsoo, Team B: Bryce, Dillon, Team C: Nitika, Viraj, Team D: Kishalay, Ilaria.

15. Class: February 24: Black holes in globular clusters-II. Team A to review paper by Kyle Kremer et al. (2019). Kremer will be attending the class.
Presentation by Kim and Somalwar

16. Class: March 1: Chemically Homogeneous Evolution
Papers: [1] Mandel & de Mink; [2] de Mink & Mandel
Mandel will be joining the class.
Presentation by DZD & BB

17. Class: March 3: Black Holes in Nuclear Clusters.
Papers: [1] A. Stephan et al. ; [2] Hoang et al.
Presentation by NY & VK

18. Class: March 8: The LVC O3 sample
Paper: Fruits of LVC run O3
Weinstein & Chatziioannou will be attending the class.

19. Class: March 10: 1:45p-3:45p Stellar Black Holes: New Frontiers in Detection (Note longer duration of this session)
1. Nitika Yadlapalli - Radio/X-ray fundamental plane
2. Kishalay De - Accretion of ISM
3. Viraj - Astrometry
4. Ilaria - Spectroscopy of binaries
5. Yoonsoo - Lensing of secondary stars
6. Bryce - Variations in eclipse timing
7. Dillon - Microlensing including Roman
8. Jean - Ellipsoidal Modulation