DOC PREVIEW
CU-Boulder ASTR 1120 - Lecture Notes

This preview shows page 1-2-17-18-19-36-37 out of 37 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 37 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

ASTR 1120ASTR 1120General Astronomy:General Astronomy:Stars & GalaxiesStars & Galaxies!NNOUNCEMENTS!NNOUNCEMENTS• HOMEWORK #6 DUE TODAY, by 5pm• HOMEWORK #7 DUE Nov. 10, by 5pmDark matter halo for galaxiesDark matter halo for galaxies••Dark matter extendsDark matter extendsbeyond visible part ofbeyond visible part ofthe galaxythe galaxy -- mass is-- mass is~10x~10x stars and gas!stars and gas!••Probably not normalProbably not normalmass that we know ofmass that we know of(protons, neutrons,(protons, neutrons,electrons).electrons).••Most likely subatomicMost likely subatomicparticles, as yetparticles, as yetunidentifiedunidentified (weakly(weaklyinteracting massiveinteracting massiveparticles particles –– WIMPsWIMPs?)?)REVIEWA Case for a A Case for a Supermassive Supermassive BlackBlackHole at the Galactic CenterHole at the Galactic Center• Doppler shiftmeasurementsof spiraling stars andgas suggest 3million MSun blackhole• Still too far out toexclude otherpossibilities…We need to be able to see closer in to reallyproveprove there is a supermasive black hole!Distance from Sgr A* (pc)Enclosed mass (Mo)Genzel 1996REVIEWStars appear to beorbiting somethingmassive butinvisible … aablack holeblack hole!Orbits of starsindicate a mass ofabout 3-4 million4 millionMMsun sun withinwithin 600600RRSchwarzchildSchwarzchildREVIEWState of AffairsState of Affairs atat the Galacticthe GalacticCenterCenter• Stellar orbits have made our Galaxy one of thebest proofs of supermassive black holes at thecenter of most galaxies.– Millions to billions of times the mass of our Sun.Must be created by something entirely differentthan a massive star supernova.• Flares are often observed in X-rays and IR– Observations of occasional flares are interpreted asthe result of occasional “swallowing” of a gas clumpor a star by the giant black hole.REVIEWIrregular GalaxiesHubbleUltraDeepFieldSpiral GalaxyElliptical GalaxyElliptical GalaxyREVIEWWhich type of galaxyWhich type of galaxycontains acontains a low percentage oflow percentage ofcool gas and dust?cool gas and dust?A. SpiralB. EllipticalC. IrregularD. Barred spiralE. Everyone but BClicker QuestionClicker QuestionWhich type of galaxyWhich type of galaxycontains a low percentage ofcontains a low percentage ofcool gas and dust?cool gas and dust?A. SpiralB. EllipticalC. IrregularD. Barred spiralE. Everyone but BClicker QuestionClicker QuestionHubble classification of galaxy typesHubble classification of galaxy typesBarred spiralBarred spiralSpiralsSpiralsEllipticalsEllipticals••SpiralsSpirals::mostly inmostly ingroupsgroups(3-10(3-10galaxies)galaxies)Where do spirals and Where do spirals and ellipticals ellipticals live?live?HST: HST: Hickson Hickson CG 44CG 44••EllipticalsEllipticals --most often inmost often indense clustersdense clustersof galaxiesof galaxies(involve 100(involve 100’’ssto 1000to 1000’’s)s)HST: HST: Abell Abell 16891689The Big PictureThe Big Picture:: Universe is Universe is filledfilled with withnetwork of galaxies in groups and clustersnetwork of galaxies in groups and clusters~100 billion galaxies!~100 billion galaxies!Pattern of galaxiesPattern of galaxies (3 million+),15 (3 million+),15oo portion of skyportion of skyBrighter =Brighter =more galaxiesmore galaxiesWhich of the following is NOT aWhich of the following is NOT aclassification of a type of galaxy?classification of a type of galaxy?A. KeplerianB. SpiralC. LenticularD. EllipticalE. Irregular Clicker QuestionClicker QuestionWhich of the following is NOT aWhich of the following is NOT aclassification of a type of galaxy?classification of a type of galaxy?A. KeplerianB. SpiralC. LenticularD. EllipticalE. Irregular Clicker QuestionClicker QuestionOur Our ““Local GroupLocal Group”” of galaxies of galaxies3 spirals:3 spirals:Andromeda (M31)Andromeda (M31)3/2 M3/2 MMWMWMilky WayMilky Way1 M1 MMWMWTriangulum Triangulum (M33)(M33)1/5 M1/5 MMWMW2 irregulars:2 irregulars:LMCLMC1/8 M1/8 MMWMWSMCSMC1/301/30 MMMWMW16+ dwarfs16+ dwarfs~21 Galaxies~21 GalaxiesBiggest is Biggest is AndromedaAndromeda ( (Sb Sb - M33)- M33)••Andromeda isAndromeda is~3 million light~3 million lightyears away (or ~30years away (or ~30MW diameters), hasMW diameters), has~1.5 mass of MW~1.5 mass of MW••We see it asWe see it as it wasit was3 million years ago,3 million years ago,not asnot as it is today! it is today! ––this isthis is lookback lookback timetime••Oops! It may Oops! It may crashcrashinto MWinto MW in about 2 in about 2billion yearsbillion yearsTriangulumTriangulum(M33)(M33)••1/5 mass of MW,1/5 mass of MW, spiralspiralclassified as Scclassified as Sc••Several bright (pink)Several bright (pink)star forming regionsstar forming regionsLarge & Small Large & Small Magellanic Magellanic CloudsCloudsLMCLMCSMCSMCLMC has 30LMC has 30DoradusDoradus, home, homeof SN 1987Aof SN 1987AWhat are theWhat are theMagellanic Magellanic CloudsClouds??A.A.Two nebulae in disk of Milky Way visible only inTwo nebulae in disk of Milky Way visible only insouthern hemispheresouthern hemisphereB.B.Clouds of dust and gas in many placesClouds of dust and gas in many placesthroughout the Milky Way galaxythroughout the Milky Way galaxyC.C.Two small galaxiesTwo small galaxies in the same group as thein the same group as theMilky WayMilky WayD.D.Star-forming clouds in constellation OrionStar-forming clouds in constellation OrionClicker QuestionClicker QuestionWhat are theWhat are theMagellanic Magellanic CloudsClouds??A.A.Two nebulae in disk of Milky Way visible only inTwo nebulae in disk of Milky Way visible only insouthern hemispheresouthern hemisphereB.B.Clouds of dust and gas in many placesClouds of dust and gas in many placesthroughout the Milky Way galaxythroughout the Milky Way galaxyC.C.Two small galaxiesTwo small galaxies in the same group as thein the same group as theMilky WayMilky WayD.D.Star-forming clouds in constellation OrionStar-forming clouds in constellation OrionClicker QuestionClicker QuestionHow do we get distancesHow do we get distances totothings far outside our Galaxy?things far outside our Galaxy?Mapping the Universe: We Mapping the Universe: Weneed Distances to Galaxies!need Distances to Galaxies!Methods we are familiar with:RadarRadar and Stellar parallaxStellar parallaxThe problem: orOnly useful inside the SolarOnly useful inside the Solar SystemSystemA few thousand A few thousand lylyNew


View Full Document

CU-Boulder ASTR 1120 - Lecture Notes

Download Lecture Notes
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Lecture Notes and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Lecture Notes 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?