Galaxies Astro 322 Winter 2011 Feb. 7
Monday, February 7, 2011 normal spirals
irregu ellipticals lars
lenticulars barred spirals “tuning-fork” diagram
Monday, February 7, 2011 Monday, February 7, 2011 Galaxies classification: key differences: total mass, gas/stars ratio, mass-to-light ratio
gas/stars ratio is connected with:
•flatness of galaxy •current SFR •ages of stellar population, colors of stars •spiral structure
Monday, February 7, 2011 Surface brightness, isophote, profile
15 Night sky at 22.7 20 µB 25
30 radius
µB
R1/4 Vaucouleurs law
Monday, February 7, 2011 elliptical galaxies sequence: oblate/prolate classification based on ratio 10 (1-b/a) of galaxy’s isophotes
M32 E2 M87 E0p NGC 4660, E7
7 13 10 - 10 Msun M110 E6
Monday, February 7, 2011 elliptical galaxies sequence: oblate/prolate classification based on ratio 10 (1-b/a) of galaxy’s isophotes
M32 E2 M87 E0p NGC 4660, E7
7 13 10 - 10 Msun M110 E6
Monday, February 7, 2011 elliptical galaxies sequence: oblate/prolate classification based on ratio 10 (1-b/a) of galaxy’s isophotes
M32 E2 M87 E0p NGC 4660, E7
7 13 10 - 10 Msun M110 E6
Monday, February 7, 2011 lenticular galaxies: some dust/gas, no spiral arms NGC 2787 SB0
Spindle galaxy, S0
NGC 4526, SB0 Monday, February 7, 2011 lenticular galaxies: some dust/gas, no spiral arms
Cartwheel galaxy (S pec ring)
Monday, February 7, 2011 Supergiant ellipticals/lenticular: centrally dominant (cD) more diffuse, larger haloes, more akin to lenticular IC 1101 Galaxy: NGC 1275: cD galaxy + high velocity system diameter 1700 kpc,1014 stars origin of cold filaments is unknown
Monday, February 7, 2011 dwarf ellipticals (dE) sometimes mentioned to be intermediate between GC and E not fully correct: dark matter
M32 Andromeda (M31)
M110
Monday, February 7, 2011 dwarf ellipticals (dE) sometimes mentioned to be intermediate between GC and E not fully correct: dark matter
M32 Andromeda (M31)
M110
M110 Е5
Monday, February 7, 2011 compact ellipticals: small sizes and high stellar densities
M32
Andromeda (M31)
M110
(By Lanoue)
Monday, February 7, 2011 compact ellipticals: small sizes and high stellar densities a small spiral in the past?
M32 compact elliptical Andromeda (M31)
M110
(By Lanoue)
Monday, February 7, 2011 dwarf spheroids (dSph): lower L than in dE, only sattelites A distinct class by stellar population and profile NGC 147 Sculptor
Different by brightness profile from Vast majority of dE and dSph are E and dE, closer to GC however closer by properties to Irr & late have dark matter type galaxies than to E! Monday, February 7, 2011
Vast majority of dE and dSph are closer by properties to Irr & late type galaxies than to E! Spiral galaxies: unbarred, spiral arm sequence from tightly wound arms to loosely wound arms
M81, Sab (Gendler) M31, Sb M101, Scd
Monday, February 7, 2011 Spiral galaxies: barred vs unbarred. a: small body, more tightly wound arms
M104, Sombrero Sa
NGC 6782 SBa
Monday, February 7, 2011 Spiral galaxies: barred vs unbarred. a: small body, more tightly wound arms
M104, Sombrero Sa
NGC 6782 SBa
Monday, February 7, 2011 Spiral galaxies: a-b
Black eye Sab
the interstellar gas in the outer regions of M64 rotates in the opposite direction from the gas and stars in the inner regions
Monday, February 7, 2011 Spiral galaxies: barred vs unbarred b subtype
M81, Sab
NGC1300, SBbc
Monday, February 7, 2011 Spiral galaxies: barred vs unbarred c: loosely wound arms Pinwheel galaxy, Scd
NGC 3319, SBc
Monday, February 7, 2011 Spiral galaxies: barred vs unbarred d: diffuse, broken arms made up of individual stellar clusters and nebulae; very faint central bulge M82, Cigar galaxy, Sd (used to be Irr in the past, near IR showed 2 spiral arms)
NGC 2805, SBd
Monday, February 7, 2011 Spiral galaxies: barred vs unbarred d: diffuse, broken arms made up of individual stellar clusters and nebulae; very faint central bulge M82, Cigar galaxy, Sd (used to be Irr in the past, near IR showed 2 spiral arms)
NGC 2805, SBd
Monday, February 7, 2011 Spiral galaxies: m - Magellanic spirals with one spiral arm
NGC 5398, SBdm
NGC 55, SBm
Monday, February 7, 2011 Spiral galaxies: unbarred with ring in such galaxies usually gas counterrotating with respect to stars
NGC 7742 SA(r)b
Monday, February 7, 2011 Ring galaxies
Hoag’s object
NGC 4650A Polar-ring galaxy
Monday, February 7, 2011 Spiral galaxies: grand design prominent and well-defined spiral arms ~10%
M51 SABbc Whirlpool galaxy
Monday, February 7, 2011 Flocculent galaxies: functional opposite of the grand design spiral galaxy ~30% patchy, with discontinuous spiral arms
NGC 4414, SAc
the rest of galaxies are multi arm galaxies, ~60%
Monday, February 7, 2011 MIlky Way
Monday, February 7, 2011 MIlky Way
SBb/SBc grand design
Monday, February 7, 2011 Irregular galaxies: Irr I (Hubble classification) have some structure subtyped in Sm (if have some spiral structure) or Im
LMC -> SBm
SMC -> Im
Monday, February 7, 2011 Irregular galaxies: Irr I (Hubble classification) have some structure subtyped in Sm (if have some spiral structure) or Im
LMC -> SBm
SMC -> Im
Monday, February 7, 2011 Irregular galaxies: Irr I (Hubble classification) have some structure subtyped in Sm (if have some spiral structure) or Im
LMC -> SBm
SMC -> Im
Monday, February 7, 2011 Irregular galaxies: Irr II (Hubble classification) no any structure
NGC 4485 (Hubble & Chandra) hosts ULXs
Monday, February 7, 2011 Irregular galaxies: dIrr dwarf irregular: very important for overal galaxy evolution. Low Z. Lots of gas.
Saggitarius
Sextans A
Monday, February 7, 2011 Monday, February 7, 2011