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Open problems in modern astrophysics

Last modified by Peter Johansson on 2025/01/15 15:25

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Information about the course

PAP302, 5 credit points, Open Problems in Modern Astrophysics

Lecturers: Prof. Peter Johansson (Room D311) (Topics 1-4)
                 Dr. Till Sawala (Room D324) (Topics 5-7)
Course assistants: M.Sc. Alexander Rawlings (Room D308)   
                               Dr. Toni Tuominen (Room D333) 
                                                                             

Lectures: Wednesdays 10.15-12.00  in Room E205 Physicum                                            
Problem sets: Wednesdays 12.15-14.00 in Room E205 on the following dates: 18.9, 2.10, 16.10, 6.11, 20.11, 4.12, 11.12 
Moodle can be accessed through the University course homepage:
https://studies.helsinki.fi/kurssit/toteutus/hy-opt-cur-2425-87489f70-c841-4593-9126-a34c49652cc1/PAP302

The course homepage will be updated as the course progresses. Note that only topics marked in blue have been updated for this
year's course.

Course grading:

The course grading is divided into two parts as follows:

  • 50% of the final grade will come from the written problem sets.
  • 50% of the final grade will come from the final written exam.

Final exam:  The final exam will be held on 18.12.2024 at 9.00-13.00 in Room E205 Physicum

Astrophysical search engines

The following astrophysical search engines can be used for searching the astrophysical literature:

Course contents

  • The aim of the course is to survey the current state of modern astrophysics, concentrating on a few interesting topics that are
    likely to remain at the forefront of astrophysical research in the coming decade. During the course the students will learn how to
    search the astrophysical literature, how to present and discuss research papers and finally also learn the necessary skills for
    writing their own research papers.
  • During the course seven different topics will be discussed for two weeks with each followed by a problem set on the topic. In the
    first lecture the Lecturer presents the topic in question based on a recent review paper typically published in the Annual Review of
    Astronomy and Astrophysics. In the second lecture the topic will be discussed in more depth using additional 1-2 papers on the topic.
    Finally, the discussion on the topic will be finished by a problem set for which the students are expected to read two papers and answer
    4 written questions on a problem sheet. In this way each topic will be covered by 1 review paper + 4-5 research papers.
  • This course will be of a strongly interacting nature and the students are encouraged to actively contribute to the lectures by reading
    in advance the papers and participate in the discussion.
  • The topics to be discussed during the course have been chosen to cover a broad range of astrophysics, including exoplanets, stars,
    galaxies and cosmology. The aim is to learn about interesting research topics that are likely to remain at the core of modern astrophysics
    in the coming decades.

Topic 1: 4.9-18.9 The detection and properties of Extrasolar planets

      
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  • 4.9 Lecture 1:
  1. Winn, J.N. & Fabrycky, D.C., 2015, ARA&A, 53, 409: "The Occurrence and Architecture of Exoplanetary Systems"   --  exoplanets_review_edit_1.pdf
  • 11.9 Lecture 2:
  1. Gillon, M., Triaud, A. H. M. J., Demory, B.-O., 2017, Nature, 542, 456: "Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1"
  2. JWST Transiting Exoplanet Community Early Release Science Team et al., 2023, Nature, 614, 649: "Identification of carbon dioxide in an exoplanet atmosphere"
  1. Anglada-Escudé, G., Amado, P.J., Barnes, J. et al, 2016, Nature, 536, 437: "A terrestrial planet candidate in a temperate orbit around Proxima Centauri"
  2. Zieba, S., Kreidberg, L., Ducrot, E. et al., 2023, Nature, 620, 746: "No thick carbon dioxide atmosphere on the rocky exoplanet TRAPPIST-1 c"
  • Useful websites for additional information:
  1. The Extrasolar Planets Encyclopedia 
  2. California & Carnegie planet-search team
  3. The Anglo-Australian Planet Search

Topic 2: 18.9-2.10 Gamma-Ray Bursts: Observation and theory

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  • 18.9 Lecture 3:
  1.  Gehrels, N., Ramirez-Ruiz, E., Fox, D.B., 2009, ARA&A, 47, 567: "Gamma-Ray Bursts in the Swift Era"   --  GRB_review_edit_2.pdf
  • 25.9 Lecture 4:
  1. Arcavi, I., Hosseinzadeh, G., Howell, D. A. et al., 2017, Nature, 551, 64: "Optical emission from a kilonova following a gravitational-wave-detected neutron-star merger"
  2. Chatterjee, S.; Law, C. J.; Wharton, R. S et al., 2017, Nature, 541, 58: "A direct localization of a fast radio burst and its host"
  3. Mösta, P., Radice, D., Haas, R. et al., 2020, 901, 37: "A Magnetar Engine for Short GRBs and Kilonovae"
  1. Greiner, J., Mazzali, P.A., Kann, D.A. et al., 2015, Nature, 523, 189: "A very luminous magnetar-powered supernova associated with an ultra-long γ-ray burst"
  2. Burns, E., Svinkin, D., Fenimore, E. et al., 2023, ApJL, 946, 31: "GRB 221009A: The Boat"

Topic 3: 2.10-16.10 Stellar dynamics near a massive black hole and gravitational waves

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  • 2.10 Lecture 5:
  1. Alexander, T., 2017, ARA&A, 55, 17: "Stellar Dynamics and Stellar Phenomena Near a Massive Black Hole" – Dyn_BH_review_edit_3.pdf
  • 9.10 Lecture 6:
  1. Abbott, B.P. et al., 2016, PhRvL, 116, 1102: "Observation of Gravitational Waves from a Binary Black Hole Merger"
  2. GRAVITY collaboration, corresponding author F. Eisenhauer, 2018, A&A, 615, 15: "Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole"
  1. Oka, T., Tsujimoto, S., Iwata, Y. et al., 2017, Nature Astronomy, 1, 709: "Millimetre-wave emission from an intermediate-mass black hole candidate in the Milky Way"
  2. Fragione, G. & Loeb, A., 2020, ApJL, 901, 32: "An Upper Limit on the Spin of SgrA* Based on Stellar Orbits in Its Vicinity"
     

Topic 4: 16.10-6.11 The formation and evolution of star clusters

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  • 16.10 Lecture 7:
  1. Krumholz, M.R., McKee, C.F., Bland-Hawthorn, J., 2019, ARA&A, 57, 227: "Star Clusters Across Cosmic Time" - Stellar_Clusters_review_edit_4.pdf
  • 30.10 Lecture 8:
  1. Lahén, N., Naab, T., Johansson, P.H., 2019, ApJL, 879, 18: "The Formation of Low-metallicity Globular Clusters in Dwarf Galaxy Mergers"
  2. Rodríguez, M.J., Lee, J.C., Whitmore, B.C., 2023, ApJL, 944, 26: "PHANGS-JWST First Results: Dust-embedded Star Clusters in NGC 7496 Selected via 3.3 μm PAH Emission"
  1. Adamo, A., Bradley, L.D., Vanzella, E., 2024, Nature, 632, 513: "Bound star clusters observed in a lensed galaxy 460 Myr after the Big Bang"
  2. Inayoshi, K., Harikane, Y., Inoue, A.K. et al., 2022, ApJL, 938, 10: "A Lower Bound of Star Formation Activity in Ultra-high-redshift Galaxies Detected with JWST: Implications for Stellar Populations and Radiation Sources"

Topic 5: 6.11-20.11 Nearby dwarf galaxies: testing the limits of structure formation.

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  • 6.11 Lecture 9:
  1. Local Group: Lecture Notes with additional material
    Based on the review: Bullock & Boylan-Kolchin, 2017, ARA&A, 55, 343-387: "Small-Scale Challenges to the ΛCDM Paradigm"
  • 13.11 Lecture 10:
  1. Review (continued)
  2. Revision Quiz: Questions summarize key points from the review. Answers have been discussed during the lecture.
  3. Belokurov, V., Walker, M.G., Evans, N.W., 2010, ApJL, 712, 103: "Big Fish, Little Fish: Two New Ultra-faint Satellites of the Milky Way"
    Two new Milky Way satellite galaxies are discovered, first in SDSS and then followed up with deeper photometric observations.
  4. Sawala T. et al. 2023, Nature Astronomy, 7, 481-49: "The Milky Way’s plane of satellites is consistent with ΛCDM"
    A possible solution to the "Plane of Satellites" problem of the Milky Way.
  1. Laevens, B.P.M., Martin, N.F., Ibata, R.A. et al., 2015, ApJL, 802, 18: "A New Faint Milky Way Satellite Discovered in the Pan-STARRS1 3π Survey"
  2. Sánchez Almeida, J., Trujillo, I., Plastino, A.R., 2024, ApJL, 973, 1, L15, 8 pp.: "The Stellar Distribution in Ultrafaint Dwarf Galaxies Suggests Deviations from the Collisionless Cold Dark Matter Paradigm"

Topic 6:  20.11-4.12 Massive galaxies at high z - a challenge for structure formation?

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  • 20.11 Lecture 11:
  1. The lectures are based on the three papers  below:
    1. Labbe et al., Nature 2023: “A population of red candidate massive galaxies ~600 Myr after the Big Bang”,
    2. Boylan-Kolchin, Nature Astronomy, 2023: “Stress testing ΛCDM with high-redshift galaxy candidates”,
    3. Lu et al., arXiv, 2024: “A comparison of pre-existing ΛCDM predictions with the abundance of JWST galaxies at high redshift”
       
  2. 27.11 Lecture 12:
  1. Continued discussion of the above papers
  2. Revision Quiz:  questions will appear here, answers will be discussed in the lecture.
  1. Carniani et al., Nature, 2024, “Spectroscopic confirmation of two luminous galaxies at a redshift of 14”

Topic 7: 4.12-11.12 Dark Energy and the Hubble Tension

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  • 4.12 Lecture 13:
  1. Review Article: Kamionkowski and Riess, Annual Review of Nuclear and Particle Science,  2023, "The Hubble Tension and Early Dark Energy
  • 11.12 Lecture 14:
  1. Revision Quiz
  1. Farooq, O. & Ratra, B., 2013, ApJL, 766, 7: "Hubble Parameter Measurement Constraints on the Cosmological Deceleration-Acceleration Transition Redshift"
  2. Darling, J., 2012, ApJL, 761, 26: "Toward a Direct Measurement of the Cosmic Acceleration"

Final results and course grading: