Extragalactic Astronomy Extragalactic Astronomy and Cosmologyand Cosmology

(PHYS 316)(PHYS 316)

Volker Beckmann

Joint Center for Astrophysics, University of Maryland, Baltimore County

& NASA Goddard Space Flight Center, Exploration of the Universe Division

UMBC, August 31st, 2006

OverviewOverview● General Information about this course● Academic Integrity● Grading● Homework / Midterms / Final● Outline of the course● Getting started with some astronomy...

Graphic: ESA / V. Beckmann

About myself...About myself...

● master in physics at Hamburg University (master thesis on X-ray astronomy) 1996● PhD in astrophysics at Hamburg Observatory and at Osservatorio Astronomico di Brera (Milan/Italy) - studying the evolution of distant galaxies (Luminosity Function of BL Lac objects and Seyfert 2 galaxies) 2001

● 2001-2003: working in Geneva (Switzerland) on a hard X-ray satellite project (INTEGRAL)

About myself...About myself...

● since October 2003: working for UMBC at NASA/Goddard Space Flight Center● distant galaxies in hard X-rays● INTEGRAL

Academic IntegrityAcademic Integrity

● By enrolling in this course, each student assumes the responsibilities of an active participant in UMBC’s scholarly community in which everyone’s academic work and behavior are held to the highest standards of honesty. Cheating, fabrication, plagiarism, and helping others to commit these acts are all forms of academic dishonesty, and they are wrong.

Academic IntegrityAcademic Integrity

● Academic misconduct could result in disciplinary action that may include, but is not limited to, suspension or dismissal. To read the full Student Academic Conduct Policy, consult the UMBC Student Handbook, the Faculty Handbook, or the UMBC Policies section of the UMBC Directory.

GradingGrading

● 30% homework: once a week, 11 assignments in total● 35% midterm: October 5 & November 7● 35% final exam: December 14-20● participation in the course is also considered!

HomeworkHomework● 30% homework● you are encouraged to work in teams of 2 - but everybody has to hand in his/her homework.● Use resources: ● course webpage● library● www - careful! Not every website tells the truth! Wikipedia might be wrong!● Use refereed / text book material whenever possible and cite correctly● include all intermediate steps (partial credit)

Course websiteCourse website

● lheawww.gsfc.nasa.gov/~beckmann/physics316● schedule● literature● homework● who’s who page● contact information

LiteratureLiterature

● Required text book:● Barbara Ryden, “Introduction to Cosmology” (2003), Addison Wesley, ISBC 0-8053-8912-1; about 65.- $● optional: Andrew Liddle, “An Introduction to Modern Cosmology”, John Wiley & Sons Ltd (about 40.- $)● nice to read: Steven Weinberg, “The First Three Minutes”, BasicBooks (about 11.- $)● have a look on the books today here after the class!

About the courseAbout the course

● Tuesdays and Thursdays 8:30 a.m. (uff!)● starts with repeating last lectures main points● discussing homework (if any)● no script - we’ll follow the text book closely● participation of students● small quiz (not relevant for your grade) on September 12th (Sep. 13 is last day to drop course without a grade of “W”)● contact me via e-mail: beckmann@milkyway.gsfc.nasa.gov● or during office hours (after lecture) in room 415

About the courseAbout the course● sophomores to seniors in this course● Prerequisite PHYS 122● basic physics (gravitation, electromagnetic waves, wave-particle dualism, elementary particles)● mathematics (some calculus)● astrophysics not mandatory, but …

● what we will not use: advanced calculus, tensor algebra, plasma physics ... ● What we will not do: learn complex formulas by heart

Getting startedGetting started

Graphic: HST

What’s cosmology ?

What do we have to know about the Universe to do cosmology ?

Key questions?

Christmas you’ll be able to Christmas you’ll be able to answer...answer...

● How is the cosmos evolving? ● What different models are there for the evolution of the cosmos and what do they predict?● What might be the future of the universe?● How can we describe the beginning of the universe?● What (anti-)particles and elements are abundant in the universe and how did they form?● What observations led to today’s cosmology?

Christmas you’ll know something Christmas you’ll know something about...about...

● Hubble law (observed increasing velocity with increasing distance of galaxies)● Friedmann equation (description of the cosmological evolution)● Dark matter● Dark energy (cosmological constant)● Inflation● Nucleosynthesis

AstronomyAstronomy

● Let’s start with some astronomy...

Foto by Scott Tucker

Foto by Steve Barrett

Phot

Foto: N.A. Sharp, NOAO/AURAU/NSF

Planets of the solar system (Pluto is not considered a planet anymore)

Graphic: NASA

The Sun - just an ordinary star!

The Sun - just an ordinary star!

The Sun - just an ordinary star!

The Sun - a fusion reactor

Mass loss of the red giant star V838

Stellar evolutionStellar evolution● Gravitation -> star formation● fusion -> main sequence evolution● heavy stars (>10 solar masses): Supernova or neutron stars● solar type stars: white dwarfs● <0.5 solar masses: brown dwarf

There are about 50 billion stellar systems in the Milkyway

Globular (star) Cluster M5

Zooming into the Globular Cluster M22

Star forming regions: the horsehead nebula in Orion

Star forming regions: the horsehead nebula in the Orion region

Star forming regions: M17

Movement of stars around the Galactic Center

Andromeda galaxy M31.

Foto: T.A. Rector, B.A.Wolpa, NOAO/AURA/NSF

M101

Foto: George Jacoby, Bruce Bohannan, Mark Hanna, NOAO/AURA/NSF

M104

Foto: Todd Boroson, NOAO/AURA/NSF

M89

Foto: NOAO/AURA/NSF

Coma Galaxy Cluster

Photo: Omar Lopez-Cruz, Ian Shelton, NOAO/AURA/NSF

Galaxy Cluster RDCS 1252.9-2927

Combined VLT optical and Chandra X-ray image

Large Scale Structure in the UniverseSimulation, Credits: F. Summers, L. Hernquist, M. White

SummarySummary

- stars (suns) undergo evolution- star formation (gravity)- fusion (H and He burning)- supernova or white dwarf- milkyway is inhomogeneous: star forming regions, globular clusters, central massive black hole - 5e10 stars in Milkyway (galaxy)- about 1e11 galaxies in the universe

SummarySummary

- galaxies come in different shape:spiral (young), elliptical (old), irregular (very young or disrupted)- galaxies form groups: galaxy clusters- a lot of gas trapped in potential of galaxy clusters