2013A&A...558A..61M -
Astronomy and Astrophysics, volume 558A, 61-61 (2013/10-1)
Spot the difference. Impact of different selection criteria on observed properties of passive galaxies in zCOSMOS-20k sample.
MORESCO M., POZZETTI L., CIMATTI A., ZAMORANI G., BOLZONELLA M., LAMAREILLE F., MIGNOLI M., ZUCCA E., LILLY S.J., CAROLLO C.M., CONTINI T., KNEIB J.-P., LE FEVRE O., MAINIERI V., RENZINI A., SCODEGGIO M., BARDELLI S., BONGIORNO A., CAPUTI K., CUCCIATI O., DE LA TORRE S., DE RAVEL L., FRANZETTI P., GARILLI B., IOVINO A., KAMPCZYK P., KNOBEL C., KOVAC K., LE BORGNE J.-F., LE BRUN V., MAIER C., PELLO R., PENG Y., PEREZ-MONTERO E., PRESOTTO V., SILVERMAN J.D., TANAKA M., TASCA L., TRESSE L., VERGANI D., BARNES L., BORDOLOI R., CAPPI A., DIENER C., KOEKEMOER A.M., LE FLOC'H E., LOPEZ-SANJUAN C., McCRACKEN H.J., NAIR P., OESCH P., SCARLATA C., SCOVILLE N. and WELIKALA N.
Abstract (from CDS):
We present the analysis of photometric, spectroscopic, and morphological properties for differently selected samples of passive galaxies up to z=1 extracted from the zCOSMOS-20k spectroscopic survey. This analysis intends to explore the dependence of galaxy properties on the selection criterion adopted, study the degree of contamination due to star-forming outliers, and provide a comparison between different commonly used selection criteria. This work is a first step to fully investigating the selection effects of passive galaxies for future massive surveys such as Euclid. We extracted from the zCOSMOS-20k catalog six different samples of passive galaxies, based on morphology (3336 ``morphological'' early-type galaxies), optical colors (4889 ``red-sequence'' galaxies and 4882 ``red UVJ'' galaxies), specific star-formation rate (2937 ``quiescent'' galaxies), a best fit to the observed spectral energy distribution (2603 ``red SED'' galaxies), and a criterion that combines morphological, spectroscopic, and photometric information (1530 ``red & passive early-type galaxies''). For all the samples, we studied optical and infrared colors, morphological properties, specific star-formation rates (SFRs), and the equivalent widths of the residual emission lines; this analysis was performed as a function of redshift and stellar mass to inspect further possible dependencies. We find that each passive galaxy sample displays a certain level of contamination due to blue/star-forming/nonpassive outliers. The morphological sample is the one that presents the higher percentage of contamination, with ∼12-65% (depending on the mass range) of galaxies not located in the red sequence, ∼25-80% of galaxies with a specific SFR up to ∼25 times higher than the adopted definition of passive, and significant emission lines found in the median stacked spectra, at least for log(M/M☉)<10.25. The red & passive ETGs sample is the purest, with a percentage of contamination in color <10% for stellar masses log(M/M☉)>10.25, very limited tails in sSFR, a median value ∼20% higher than the chosen passive cut, and equivalent widths of emission lines mostly compatible with no star-formation activity. However, it is also the less economic criterion in terms of information used. Among the other criteria, we found that the best performing are the red SED and the quiescent ones, providing a percentage of contamination only slightly higher than the red & passive ETGs criterion (on average of a factor of ∼2) but with absolute values of the properties of contaminants still compatible with a red, passively evolving population. We also find a strong dependence of the contamination on the stellar mass and conclude that, almost irrespective of the adopted selection criteria, a cut at log(M/M☉)>10.75 provides a significantly purer sample in terms of star-forming contaminants. By studying the restframe color-mass and color-color diagrams, we provided two revised definitions of passive galaxies based on these criteria that better reproduce the observed bimodality in the properties of zCOSMOS-20k galaxies. The analysis of the number densities of the various samples shows evidences of mass-assembly ``downsizing'', with galaxies at 10.25<log(M/M☉)<10.75 increasing their number by a factor ∼2-4 from z=0.6 to z=0.2, by a factor ∼2-3 from z=1 to z=0.2 at 10.75<log(M/M☉)<11, and by only ∼10-50% from z=1 to z=0.2 at 11<log(M/M☉)<11.5.
(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases
Other object types:
reg
()
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
quality : flag of quality
E ≥ 10"
D : 1-10" (and some old data)
C : 0.1-1"
B : 0.01-0.1" + 2MASS, Tyc
A : VLBI, Hipparcos
bibcode : bibcode of the coordinates reference
FK4
coord.
(ep=B1950 eq=1950) :
09 57 53.49 +02 26 47.1
[
]
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
quality : flag of quality
E ≥ 10"
D : 1-10" (and some old data)
C : 0.1-1"
B : 0.01-0.1" + 2MASS, Tyc
A : VLBI, Hipparcos
bibcode : bibcode of the coordinates reference
Gal
coord.
(ep=J2000) :
236.82224 +42.12163
[
]
', {sourceSize:12, color:'#30a090'})); aladin.on('objectClicked', function(object) { var objName=object.data.MAIN_ID; aladin.showPopup(object.ra,object.dec,'',''+ objName+''); });" title="Show Simbad objects">
Overlay
points in this preview
All
(CDSPortal)
Send to
The link on the acronym of the identifiers give access to the
information for this acronym in the dictionary of nomenclature.
Identifiers (1) :
An access of full data is available using the icon Vizier near the identifier of the catalogue
References (2972 between 1850 and 2024) (Total 2972)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
Follow
new references on this object
Annotations :
Annotations allow a user to add a note or report an error concerning the astronomical object and its data. It requires registration to post a note. See description . Please, have a look at Best practices. The list of all annotations to SIMBAD objects can be found here .
To bookmark this query, right click on this link: simbad:objects in 2013A&A...558A..61M and select 'bookmark this link' or equivalent in the popup menu