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The morphological dependent Tully-Fisher relation of spiral galaxies


Bulge contamination effect, disks are similar (Deverux & Young 1991) ... 8th Sino-German Workshop. 11. our model: dynamics ... Model predicted morphological ... – PowerPoint PPT presentation

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Title: The morphological dependent Tully-Fisher relation of spiral galaxies

The morphological dependent Tully-Fisher relation
of spiral galaxies
  • Shiyin Shen
  • Collabroators Ruixiang Chang, Jinliang Hou
  • Shanghai Astronomical Observatory
  • Kunming, 2/23/2009

  • Tully-Fisher (TF) relation correlation between
    the maximum rotation velocity and absolute
    magnitude (Tully Fisher 1977)
  • M a Log Vmax b
  • small scatter, rms 0.3 mag at near infrared
  • distance estimator Hubble constant
  • Morphological type of spiral galaxies
  • Hubble system Sa/Sb/Sc/Sd/Irr
  • RC3 system T 0 ? 10 S0 ? Irr
  • From early to late type
  • Smaller relative bulge size
  • Larger pitch angle of spirals
  • Coupled with spiral luminosity earlier type
    galaxies are biased to brighter galaxies

Morphological dependence of TF relation
  • Discovered by Roberts (1978), confirmed by Rubin
  • for samples of the same absolute magnitude,
    late-type galaxies have systematically smaller
    intrinsic line widths than early-type systems
    (Roberts, 1978).
  • At given Vmax , a Sa galaxy is 2 mag fainter in B
    band and 1 mag fainter in H band than typical Sc
    galaxy (Rubin, 1985)
  • In I band
  • Giovanelli et al. (1997) found a 0.32 mag
    smaller zero point for Sa/Sab galaxies and 0.10
    mag smaller for Sb galaxies relative to Sbc and
    later type spirals.(555 spirals)
  • Russel(2004) found Sb galaxies have a zero point
    0.57 mag smaller than Sc galaxies in B band .

Morphological dependence further dependent on
  • SFI sample 5000 spiral galaxies suitable for
    TF study in I band (Masters et al. 2006)
  • morphological dependence further on magnitudes
  • Sa to Sc -0.32-0.9(logW-2.5)mag
  • Sb to Sc -0.1-0.9(logW-2.5) mag
  • Morphological dependence is more pronounced for
    more massive galaxies

Morphological dependence K-band (Russell, 2008)
  • Compare the mean TF distances of the clusters and
    groups when using ScI galaxies and Sb galaxies
  • Calibrated by Cepheid distance
  • Mean difference 0.19mag
  • Effects from dynamics (Vmax) or stellar
    population (M)?

Type dependence dynamics
  • Early type spirals with large bulges have
    rotation curves that rise more rapidly than late
    type spirals with similar L (Corradi Capaccioli
  • Sa galaxies show difference from universal
    rotation curve(Persic Salucci 1991, 1996), rise
    rapidly in central regions, decline about 10-20
    percent from Vmax at intermediate radii, flatten
    out at large radii (Noordermeer et al. 2007).
  • High mass early type spiral galaxies lie on the
    TF relation only if asymptotic rotation velocity
    Vasymp? Vmax (Noordermeer Verheijen 2007)

Rotation curve of Sa galaxies
High mass disks
Stellar population of spiral disks
  • Different morphological type spiral galaxies show
    systematical different colors
  • Earlier type spiral with redder colors
  • Bulge contamination effect, disks are similar
    (Deverux Young 1991).
  • Different stellar population (star formation
    history) of the disks of different types
    (Kennicutt Tamblyn 1994)
  • bSFR/ltSFRgtpast
  • Measurement of b B-V color, EW(H?)

For SFR(t)exp(-t/?) b0.33?? 5 Gy b1 ? ?
Kennicutt Tamblyn 1994
Type dependence of inverse TF relation (Theureau
et al. 1997)
  • Diameter (inverse) Tully-Fisher relation
  • Vmax - Diameter (25 magarcsec-2) relation
    logVmaxalog D b
  • Type dependent early type galaxies have larger
    Vmax at given diameter
  • The surface brightness of spiral galaxies at D25
    is mainly contributed by disks.
  • so it is unlikely that the Bulge Disk
    composition could significantly contribute to any
    type dependence simply through the shift in D25
  • The type dependence of inverse TF relation is
    caused by Vmax
  • Basic assumption Vmax appears at constant radius
    rm and rm is proportional to rd. (?)
  • Earlier type galaxies have larger bulge
    component, so that have larger Vmax at given D25
  • ? log Vmax0.5? log(1? Ld/Lb) ?Yb/Yd Y
    - mass to light ratio
  • If ?1, this model will not predict any type
    dependence of TF (Vm-Mag) relation

our model dynamics
  • Components disk, bulge, dark matter,
  • Disk exponential disk
  • Flattened disk geometry
  • Bulge de Vaucouleurs profile
  • Dynamics Hernquist model (1990)
  • Dark matter initial NFW profile, adiabatic
    contraction when disk formation (Mo, Mao White
  • Disk angular momentum
  • ?0.05
  • Bulge/disk ratio
  • Sb(0.3), Sc(0.1)
  • Baryon fraction ? dark matter
  • 0.13/1(Mh/1012Msun)-2/3
  • Size-mass relation (Shen et al. 2003)

Model prediction rotation curves
  • For the halo with the same Mass (Vc) and angular
    momentum (?), the rotation curve of earlier type
    spiral galaxies rise more rapidly as observed
  • But the maximum rotation velocity, appears at
    3Rd, depends weakly on the bulge component
  • The morphological type of spiral galaxies may
    have intrinsic correlation with the initial
    angular momentum (?) of the host halos(?)

Our model stellar population
  • Stellar population model (Bruzual Charlot,
  • Bulge
  • Single stellar population, 10Gy
  • Disk
  • Star formation history SFR(t) exp(-t/?)
  • Kennicutt Tamblyn 1994
  • Sb ? 5 Gy ? b0.3
  • Sc ? 100 Gy ? b1, constant star formation
  • 10Gy old

Model predicted TF relation of Sc galaxies
  • The slope of the TF relation is nicely reproduced
  • The zero-point of the TF relation suggests
  • the time scale of the disk star formation of Sc
    spirals ?gt5Gy

Model predicted morphological dependent TF
  • The B/D composition effect only is not enough to
    explain the shift of the zero-point of the TF
  • The stellar population of later galaxies should
    be younger
  • The difference of the stellar population of the
    spiral disks(Sb/Sc) is not as large as that
    suggested by Kennicutt Tamblyn 1994
  • If so, the difference of the zero-point of TF
    relations is over-predicted

  • Understand the morphological dependent
    Tully-Fisher relation is very important when use
    it as a distance estimator.
  • The maximum rotation velocity shows weak
    dependence on the morphologies of spirals, at
    least for those later than Sb.
  • The stellar population of the later type spiral
    disks is averagely younger than earlier types.
    The morphological dependent TF relation provides
    a statistical constraint on this difference.

  • Test the disk instability model (Shen et al.
  • The bulge is formed through disk instability. The
    B/D ratio is determined by the properties of
    disks, e.g. the value of ?. later spirals are
    biased to those with large ?.
  • The current model assumes the same ? for all
    types, implies that bulge formation is
    independent of disk properties (merge scenario?)
  • Difference between Sa/Sb
  • Need more observational constraints
  • What?