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).