Barred Spiral Galaxy: Has a Bar of Stars Across Hubblethe Ultra Bulge Deep Field Classiﬁcation of Spirals

A “zoo” of galaxies Are all the other galaxies in the Are all the other galaxies in the UniverseA “zoo” similar of galaxies to the Milky Way? Universe Hubblesimilar Ultra Deep to Field the Milky Way? elliptical galaxy spiral galaxy Hubble Ultra Deep Field Hubble Ultra Deep Field Are all the other galaxies in the Universe similar to the Milky Way? M 87 - (in Virgo cluster) - spheroid - no disc - red-yellow color—> old stars Hubble Ultra Deep Field The shape of elliptical galaxies M 87 Ellipticity = 1 - b/a ellipticity ✏ =1 b/a − E0,E1,E2,...En E0 E1 E2 a b … E7 n = 10✏ Hubble Ultra Deep Field Classification of Ellipticals ellipticity ✏ =1 b/a − E0,E1,E2,...En n = 10✏ Are all the other galaxies in the Universe similar to the Milky Way? • Lenticular Lenticular Galaxy galaxy: has a disk like a spiral galaxy but much less dusty gas (intermediate - intermediate between spirals and ellipticals between - dusty stellar disc - less dusty spheroid spiral and elliptical) Hubble Ultra Deep Field Are all the other galaxies in the Universe similar to the Milky Way? Spirals Hubble Ultra Deep Field Grand design spirals Grand Design Spirals M51 Are all the other galaxies in the Universe similar to the Milky Way? Barred Spiral • Barred spiral galaxy: has a bar of stars across Hubblethe Ultra bulge Deep Field Classification of Spirals disk/bulge pitch angle disc/bar The Hubble’s sequence Hubble Sequence (not evolutionary!) This is NOT an evolutionary sequence Irregulars Cluster of galaxies HST MCS J0416.1–2403 GravitationalGa Dynamics 1. Virial theorem 2. Time scales for relaxation see notes 3.4 Scaling Relations 107 gas, which can be determined from the strength of the 3.4.3 The Fundamental Plane 21-cm line, to the stellar mass a much tighter correlation The Tully–Fisher and Faber–Jackson relations specify is obtained, see Fig. 3.21(b). It reads aconnectionbetweentheluminosityandakinematic 4 9 2 vmax property of galaxies. As we discussed previously, vari- Mdisk 2 10 h− M , (3.19) = × ⊙ 100 km/s ous relations exist between the parameters of elliptical ! " galaxies. Thus one might wonder whether a relation ex- and is valid over five orders of magnitude in disk mass ists between observables of elliptical galaxies for which M M M .Ifnofurtherbaryonsexistinspirals disk gas the dispersion is smaller than that of the Faber–Jackson (such= as, e.g.,∗ + MACHOs), this close relation means that relation. Such a relation was indeed found and is known the ratio of baryons and dark matter in spirals is constant as the fundamental plane. over a very wide mass range. Scaling Relations for GalaxiesTo explain this relation, we will consider the vari- ous relations between the parameters of ellipticals. In 3.4.2 The Faber–Jackson Relation Sect. 3.2.2 we saw that the effective radius of normal el- Arelationforellipticalgalaxies,analogoustotheTully– lipticals is related to the luminosity (see Fig. 3.7). This Fisher relation, was found by Sandra Faber and Roger implies a relation between the surface brightness and Jackson. They discovered that the velocity dispersion in the effective radius, the center of ellipticals, σ0,scaleswithluminosity(see 0.83 Re I − , (3.21) Spirals Fig. 3.22), Ellipticals: ∝ ⟨ ⟩e SMBHs Tully-Fischer L σ 4 , Faber-Jackson where I is the average surface brightness withinM the σ relation 0 3.4 eScaling Relations ∝ effective⟨ ⟩ radius, so that or 107 − gas, which can be determined from the strength of the 3.4.3 The Fundamental Plane 21-cm line, to the stellar mass a much tighter correlation 5.64 The Tully–Fisher and Faber–Jackson relations2 specify 4 log(σ0) 0is. obtained,1MB see Fig.const 3.21(b).4 It. reads (3.20) L 2πR I . 8.32 (3.22) σ L v = − L+ σ aconnectionbetweentheluminosityandakinematice eM 10 M rot(max) 4 = ⟨ ⟩ BH 9 2 0 vmax property of galaxies. As we discussed previously, vari- 1 Mdisk 2 10 h− M , (3.19) / “Deriving” the Faber–Jackson= /× scaling⊙ 100 km/s relation isous pos- relations exist between the parameters of elliptical ⇡ 200 km s− ! " galaxies. Thus one might wonder whether a relation ex- and is valid over five orders of magnitude in disk mass From this, a relation between the luminosity and I e sible under the same assumptions as the Tully–Fisherists between observables of elliptical galaxies for which ⇣ ⌘ Mdisk M Mgas.Ifnofurtherbaryonsexistinspirals ⟨ ⟩ ∗ the dispersion is smallerresults, than that of the Faber–Jackson (such= as, e.g.,+ MACHOs), this close relation means that relation. However, the dispersion of ellipticalsrelation. about Such a relation was indeed found and is known the ratio of baryons and dark matter in spirals is constant as the fundamental plane. this relation is largerover a very than wide mass that range. of spirals about the 2 0.66 To explain this relation,L we willRe considerI e the vari-I e− ous relations between the parameters∝ ⟨ of ellipticals.⟩ ∝ ⟨ In ⟩ Tully–Fisher relation.3.4.2 The Faber–Jackson Relation Sect. 3.2.2 we saw that the effective radius of normal el- Arelationforellipticalgalaxies,analogoustotheTully– lipticals is relatedor to the luminosity (see Fig. 3.7). This Tully–Fisher Relation E NCYCLOPEDIA OF A STRONOMY AND A STROPHYSICS Fisher relation, was found by Sandra Faber and Roger implies a relation between the surface brightness and Jackson. They discovered that the velocity dispersion in the effective radius, McConnell & Ma 2012 M Pierce, P Murdin - Encyclopedia of Astronomy and Astrophysics Schneider 2006 1.5 the center of ellipticals, σ0,scaleswithluminosity(see 0.83 Re I − , I e L− (3.21). (3.23) Fig. 3.22), ∝ ⟨ ⟩e ⟨ ⟩ ∝ 4 L σ0 , where I e is the average surface brightness within the ∝ effective⟨ ⟩ radius, so that or Hence, more luminous ellipticals have smaller surface 2 log(σ0) 0.1MB const . (3.20) L 2πR I . (3.22) = − + = e ⟨ ⟩brightnesses,e as is also shown in Fig. 3.7. By means “Deriving” the Faber–Jackson scaling relation is pos- From this, a relation between the luminosity and I sible under the same assumptions as the Tully–Fisher of the Faber–Jacksone relation, L is related to σ0,the results, ⟨ ⟩ relation. However, the dispersion of ellipticals about central velocity dispersion, and therefore, σ , I ,and this relation is larger than that of spirals about the 2 0.66 0 e L Re I e I e− ⟨ ⟩ Tully–Fisher relation. ∝ ⟨ ⟩ ∝ ⟨R⟩ are related to each other. The distribution of elliptical or e 1.5 galaxies in the three-dimensional parameter space (Re, I L− . (3.23) ⟨ ⟩e ∝ I e, σ0) is located close to a plane defined by Hence, more luminous⟨ ⟩ ellipticals have smaller surface brightnesses, as is also shown in Fig. 3.7. By means of the Faber–Jackson relation, L is related to σ0,the central velocity dispersion, and therefore,1.4σ0, I e,and0.85 Tully–Fisher Relation E NCYCLOPEDIA OF A STRONOMY AND A STROPHYSICS Re σ0 ⟨I⟩ e− . (3.24) Re are related to each other. The distribution of⟨ elliptical⟩ galaxies in the three-dimensional∝ parameter space (Re, I , σ ) is located close to a plane defined by ⟨ ⟩e 0 1.4 Writing0.85 this relation in logarithmic form, we obtain Re σ I − . (3.24) ∝ 0 ⟨ ⟩e Fig. 3.22. The Faber–Jacksonmagnitude relation~ log (Luminosity) expresses a relation between the velocity dispersion and the luminosity of ellipticalWriting this relation in logarithmic form, we obtain Fig. 3.22. The Faber–Jackson relation expresses a relation be- log Re 0.34 µ e 1.4logσ0 const , (3.25) tween the velocity dispersion and the luminosity of elliptical galaxies. It can be derived from the virial theorem log Re 0.34 µ e 1.4logσ0 const= , (3.25)⟨ ⟩ + + galaxies. It can be derived from the virial theorem = ⟨ ⟩ + + magnitude ~ log (Luminosity) ~ log( projection corrected rotational velocity ) Fig. 1.— The M σ relation for our full sample of 72 galaxies listed in Table A1 and at http://blackhole.berkeley.edu.Brightest Figure 1. B, R, I and H band calibrations of the Tully–Fisher relation. Solid circles are galaxies with distances measured using cluster galaxies (BCGs)• − that are also the central galaxies of their clusters are plotted in green, other elliptical and S0 galaxies are plotted in red, and late-type spiral galaxies are plotted in blue. NGC 1316 is the most luminous galaxy in the Fornax cluster, but it lies at the Cepheids, solid triangles are galaxiesFigure 1. B with, R, I and distancesH band calibrations estimated of the Tully–Fisher via relation. surface Solid circles brightness are galaxies with fluctuation distances measured measurements using within dE companions Fig. 1.— The M σ relation for our full sample of 72 galaxies listed in Table A1 and at http://blackhole.berkeley.edu.Brightest • cluster outskirts; the green symbol here labels the central galaxy NGC 1399. M87 lies near the center of the Virgo cluster, whereas NGC Cepheids, solid triangles are galaxies with distances estimated via surface brightness fluctuation measurements within dE companions cluster galaxies (BCGs)− that4472 are (M49) also lies the1Mpctothesouth.Theblack-holemassesaremeasuredusingthedynamicsofmasers(triangles),stars(stars)orgas central galaxies of their clusters are plotted in green, other elliptical and S0 galaxies are plotted ⇠ and open circles are systems thoughtand open circlesto be are groupsystems thought members to be group members with withat least at least one one galaxy galaxy with a Cepheid with distance, a Cepheid and therefore thoughtdistance, to and therefore thought to (circles). Error bars indicate 68% confidence intervals. For most of the maser galaxies, the error bars in M are smaller than the plotted in red, and late-type spiral galaxies are plotted in blue.

Load more