Cosmology 2002 - 2003

Cosmology 2002 - 2003Prof. Guido Chincarini

The scope of these lectures is to give to the student a feeling for modern problems in cosmology, understand the basic concepts and give to him some tools to work with. Often I will deal with a rough approximation in deriving equations and numerical solutions. That is to facilitate the comprehension. The student can refer to advanced textbooks and articles to refine his/her computational capabilities.The Introduction give a general overview of the state of the art referring to basic matters and problems which are being studied now days. I will then, before getting to the world models, revisit the Luminosity Function of galaxies in its more general meaning in order to give to the students a good grasp on this fundamental distribution function and ideas on where our knowledge could and/or need to be improved.

Cosmologia A.Year 02_03 - Milano Bicocca

Notes & ReferencesI will still work on these lectures during the next semester,. Indeed various parts need to be improved, other expanded and above all I must add an large number of references to help the students and also to acknowledge the contribution of others when needed and due.On the other hand I realize that many students and colleagues like to have them the way they are and eventually get the updates later on when ready. I understand that so that I decided to put them on the Web. I appreciate if they are quoted when used and if the students, or anyone for that matter, let me know about errors and typos.Also let me know ways to improve them.


CosmologiaNotizie PraticheCoordinates: [email protected] - Phone: 039 999 111 FAX 039 9991160Lectures: Monday & Wednesday 10:45 12:45 or TBDNotes: The students will give a short (20 minutes lecture) at the end of the semester.Exams: Can be done with appointment any time the student wants. The exam consists of a discussion on a topic selected by the student (generally the content of the lecture the student presented at the end of the semester) and on some of the arguments dealt during the regular lectures.Relax: Picnic at the Observatory in Merate hopefully will continue. Eventually we organize a joint gathering. Everybody is welcome.


Shall we try?The literature and the web is very rich. Data and catalogues are available at any wavelength (Radio, HST, XMM, Chandra etc) and tools to analyze them, as for instance ASDC, are also at hand. There are beautiful pictures as well.The idea is: Could we try, as a group, to tackle or re-work a cosmological problem or Could we try to tackle many different and simpler problems with pairs or single students orBetter forget aboutThe Risks:We might fail because the problem (or problems) is not well chosenSince I am very busy I might not find the time to follow properly the students. I might not be capable of carrying out on this first attempt what I have in mind.We discover it is a silly idea. I did not star to plan on it yet.The Reason for this:Things in science and in life are changing and we have to find new ways not only to organize ourselves but also to teach, become creative and find a way of thinking and operating with broader view.


Im astounded by people who want to know the Universe when its hard enough to find your way around Chinatown. (Woody Allen)


Composizione artistica della NASA


The evolving UniverseMilestonesBig Bang. (0.0) Plancks time (10-43 sec)Nucleosynthesis - He - Gamow. (~100 sec)Time of Equivalence. (7000 - 10000 years)Time of Recombination. (~25000 years) - MWBThe formation of galaxies and Large Scale Structures.(~500 Ml years)The present (~ 12 109 years)


Il Ciclo della Materia

Interstellar MediumStarsGiant StarsSupernovaeInterstellar Medium Stars.

Brown dwarfsWhite DwarfNeutron StarsBlack HolesBig Squeeze or the VacuumLe Tappe Finali


The simulated image shows what the accretion disk around a black hole might look like. The distortions of time and space by the intense gravity of the black hole and motion of the material at close to the speed of light cause emission to be shifted to longer and shorter wavelengths.


Some of the Big Questions

The Cosmological constantThe Nature of Dark MatterMWB Fluctuations on small scalesThe formation and evolution of:GalaxiesClusters of Galaxies The Large Scale Structure High z Galaxies & StarburstsPrimordial Black HolesThe Gamma Ray Bursts

The Galactic Center (IR)

Cosmological Tests leading to qoHubble DiagramGalaxy counts-magnitudeThe angular diameters - z relationAge of the oldest objectsLensing


The amount of matter/energy in the universe determines the rate at which the expansion of the universe is decelerated by the gravitational attraction of its contents, and thus its future state: whether it will expand forever or collapse into a future Big Crunch.


The Hubble Diagramin the low red-shift limit(V=HoxD)Hubble&Humason1931


530 km/s Mpc


The Hubble Diagram at high z For an object of known absolute magnitude M, a measurement of the apparent magnitude m at a given z is sensitive to the universal parameters, through the luminosity distance:


GRBs ??


z=6.28

The IGM Absorption (z=3,4,5,6)

Moriond 2002

Star Formation RateThe distribution has been obtained by fitting the curve proposed by Lamb and Reichart and adding a Gaussian distribution in the range 15

RedshiftsLa Forest


How many photons do we get

The Number of photons we receive as a function of the apparent magnitude:Assume a 4 meters telescope and a 900 A wide filter.Now lets put a 40W light at the distance of the Moon (3.84 105 km) We will get about 225 photons per second. More or less an object with mv=20.6 (we assumed 30% efficiency for the optics).The new Moon night sky far from any city or human light pollution has mv=21.7 That is about 60 photons per second.

Distant Galaxy with ISAAC


See Black Body Radiation


Da: Materia Oscura ed Energia OscuraGuido Chincarini


Basic Properties of Clusters

Property

Indicative values

Richness

30 300 galaxies between m3 and m3+2 in 1.5h-1Mpc radius

Morphology

CD Clusters Regular => Irregular

Population

E (35% to 15%), SO(45% to 35%), Sp(20% to 50%)

Line of sight vel. dispersion

In the range 1300 500, km/sec

Number counts profile

Projected: n=no (1+r2/Rc2)-3/2, Rc = core radius

Mass (within 1.5 h-1 Mpc)

1014 2 1015 h-1 M(

Luminosity (r (1.5 h-1 Mpc)

In B filter: 5 1011 5 1012 h-2 L(

X-ray gas S.B. profile

[1+r2/Rc2]-3(+1/2

(

(r/(kTx/(mp)

Central density (ne core)

~ 10-3 h1/2 cm-3

X-ray Temperature

~2 to 14 keV, 2 107 108 K

X-ray Luminosity

~1042 1045 h-2 erg s-1

Mass o f the gas & Mgas/Mgal

1013 1014 M( h-2.5, 0.05 0.2 h-1.5 (( 1.5 h-1 Mpc)

Cluster Number density

10-6 10-7 h3 Mpc-3 [ rich clusters]

Iron Aundance

0.2 0.5 solar

Distant Galaxy with Gravitational Lens - Einstein Ring - A way to Map Matter


The Coma Cluster of Galaxies - PSS & CHANDRA


X - Ray PhotonsOptical Photons


Merger of two sub_clusters. The sub-clusters are embedded within Abell 2142. The subclusters might have collided two or three times in the past few billion years. The bright source in the upper left quadrant is an active galaxy belonging to the cluster.White 50 million Degrees, Magenta 50 Million Degrees to 100.


Gamma Ray Burst at z=1.6, GRB 990511


GRB PolarizationObserving the afterglow of GRB990510 with the VLT soon (~ 18 h) after the burst detection, a small but significant amount of linear polarisation was detected in the optical (R) band, Covino et al.,Wijers et al. 1999. There are two major consequences of this observation: first, it is a confirmation of the synchrotron origin of the radiation, since synchrotron photons can be highly polarised. Second, associated with a somewhat anomalous steeping of the light-curve, it gives a strong indication for the fireball to be beamed.


GRB Model


Cosmology 2002 - 2003

Documents

single students orbetter

simpler problems

modern problems

regular lectures

milano bicoccashall

general overview

minutes lecture

general meaning