Jaime Izquierdo, Jesús Gallego, Jaime Zamorano Dpto. Astrofísica y CC. de la Atmósfera, Universidad Complutense
de Madrid
Flux-weighted virial masses from emission lines as a tracer of stellar
masses for star-forming galaxies
The UCM survey
Sample of galaxies with active stellar formation in the Local Universe selected by Hα emission
Calar Alto, Schmidt 80/120 cm (1950 Å/mm).471.4 (0.4 ELGs/) 191 galaxiasz < 0.045 EW (Ha+[NII]) > 20 Å.
r
Ha
-Stellar formation galaxies identification-Stellar formation rate-Luminosity Function-Morfology-Fisical Properties : Stellar Mass
Aims Data and Observations
Telescop INT 2,5m
Instrument IDS-500mm
Detector TEK #3
Spatial scale 0,33 arcsec/píxel
Spectral Resolution 1,2 Å
Anchura de la rendija 1 arcsec
RunMAY97AGO98DEC07MAR08
Observed galaxies 45 834729 175 in Total
“Disk-like” Galaxies
Low excitation
High metalicity
Virial Mass Mv = C2 σ2 Re
C2 constantRe efectiv radio (kpc)
Flux-weighted virial Mass σ Σi (Fi σi) / Σfiσi velocity dispersion
Colapsed Virial Massσ obtained from colapsed spectra
•This research provides a relationship between virial and stellar masses
• We have obtained a calibration applicable tofutures galaxies surveys at different z:
logMe=0.808 logMvF+ 1.794 (Chabr.)
logMe=0.804 logMvF+2.084 (Salpet.)
Conclusions •Dynamical masses of the galaxies studied in this work, are consistent with the stellar masses photometrically estimated by Pérez-González (2013)
•We have demonstrated that the rotation curve by H emission line αis enough good accuracy with the real galaxy rotation curve.
•Dynamical masses obtained are lower than virial masses. There are no evidence of any reason. A motive could be that this galaxies present a starburst in the nuclei that control the velocity dispersion obtained from the spectra.
•We have demonstrated the utility of the stellar and virial masses methods to calculate the mass of a sample of galaxies.
- Star-forming Galaxy Masses of the Local Universe.- Virial Masses from the cinematic of ionized gas.- Dynamical Masses from rotational curves. - Calibration applicable to futures galaxies surveys at different z.- Comparison with stellar masses photometrically estimated by Pérez-González (2003 Doctoral Thesis).
“HII-like” Galaxies
High excitation Low metalicity
-300
-200
-100
0
100
200
300
-8 -6 -4 -2 0 2 4 6 8
De
lta
de
V (
km
/s)
Delta de Y (kpc)
Curva de rotación UCM 1443+2844
ΔVrot velocidad de rotación (km/s)
ΔR distancia al centro (kpc)
Md = ΔV2rot ΔR / G
Dynamical Mass
UCM 2304+1640
UCM 2253+2219
Ma Diná vs Virial_F
7
8
9
10
11
12
7 8 9 10 11 12
log Masa Virial_F
log
M
as
a D
iná
mic
a
Dynamical Masses vs Virial_PondF
Dinamical mases are lower than virial flux-weigthed mases in 66% of galaxies.
Masas Estelares vs Viriales PondF
Masa Diná vs Virial Colapsada.
7
8
9
10
11
12
7 8 9 10 11 12
log Masa Virial Colapsada
log
Ma
sa
Din
ám
ica
Dynamical Masses vs Virial Colaps
Diyamical masses are lower than Virial colapsed masses in 76% of galaxies.
The Flux Weighted Virial Masses are lower than stelar mases in 53% of galaxies (24% in HII type and 29% in Disc type). IMF from Chabrier.
Disk-LikeHII-Like
Flux-weighted virial masses are lower than stellar masses in el 36% of galaxies (19% in HII type and 17% in Disc type). IMF from Salpeter
Disk-LikeHII-Like
Masas Dinám vs Estelares
7
8
9
10
11
12
7 8 9 10 11 12
Log Masa Estelar
Lo
g M
asa D
inám
ica
Disco
HIIH+BCD
Dynamical Masses vs Stellar M.
Dinamical mases are lower than stellar masses in 82% of galaxies (66% in HII type and 86% in Disc type).