1,072 research outputs found
One of Us: Social Identity, Group Belonging and Leadership
The title of this paper suggests a paradox. Leaders are simultaneously separate from and the same as their followers. They have higher status, greater influence, and more power, and occupy a different role, but they are also members of and identify with the same group as their followers. George W. Bush, as president, is certainly quite separate from most Americans, but he identifies himself as an American, and he spends a great deal of time making sure all Americans know this. However, if we take a fairly common
type of definition of leadership as “a process of social influence through which an individual enlists and mobilizes the aid of others in the attainment of a collective goal” (Chemers, 2001, 376), then we can see that Bush is only really a leader to those who will follow—those who share his definition of American and therefore those who share his identity, group membership, and collective goal
Social identity and attitudes
This is the author's post-print version. Details of the definitive version are available at: http://www.psypress.com/978184169481
The Extremely Red Objects Found Thus Far in the Caltech Faint Galaxy Redshift Survey
We discuss the very red objects found in the first field of the Caltech Faint
Galaxy Redshift Survey, for which the observations and analysis are now
complete. In this field, which is 15 arcmin and at J005325+1234 there are
195 objects with mag, of which 84% have redshifts. The sample
includes 24 spectroscopically confirmed Galactic stars, 136 galaxies, three
AGNs, and 32 objects without redshifts.
About 10% of the sample has mag. Four of these objects have
redshifts, with . Three of these are based on absorption
features in the mid-UV, while the lowest redshift object shows the standard
features near 4000\AA. Many of the objects still without redshifts have been
observed spectroscopically, and no emission lines were seen in their spectra.
We believe they are galaxies with that are red due to their
age and stellar content and not to some large amount of internal reddening from
dust.
Among the many other results from this survey of interest here is a
determination of the median extinction in the mid-UV for objects with strong
emission line spectra at . The result is extinction by a factor
of 2 at 2400\AA.Comment: 6 pages, Latex, with 2 figures. To be published in the proceedings of
the conference "Infrared Surveys: A Prelude to SIRTF
Near Infrared Imaging of the Hubble Deep Field with The Keck Telescope
Two deep K-band () images, with point-source detection limits of
mag (one sigma), taken with the Keck Telescope in subfields of the
Hubble Deep Field, are presented and analyzed. A sample of objects to K=24 mag
is constructed and and colors are measured. By
stacking visually selected objects, mean colors can be measured to
very faint levels; the mean color is constant with apparent
magnitude down to mag.Comment: Replaced with slightly revised source positions and corrected V-I
magnitudes (which were incorrect in the Tables and Figure 5). 18 pages. The
data are publicly available at http://www.cco.caltech.edu/~btsoifer/hdf.html
along with a high-resolution version of Fig.
The oxygen-II luminosity density of the Universe
Equivalent widths of [OII] 3727 A lines are measured in 375 faint galaxy
spectra taken as part of the Caltech Faint Galaxy Redshift Survey centered on
the Hubble Deep Field. The sensitivity of the survey spectra to the [OII] line
is computed as a function of magnitude, color and redshift. The luminosity
function of galaxies in the [OII] line and the integrated luminosity density of
the Universe in the [OII] line are computed as a function of redshift. It is
found that the luminosity density in the [OII] line was a factor of ~10 higher
at redshifts z~1 than it is at the present day. The simplest interpretation is
that the star formation rate density of the Universe has declined dramatically
since z~1.Comment: accepted for publication in Ap
Counts and Colors of Faint Galaxies in the U and R Bands
Ground-based counts and colors of faint galaxies in the U and R bands in one
field at high Galactic latitude are presented. Integrated over flux, a total of
1.2x10^5 sources per square degree are found to U=25.5 mag and 6.3x10^5 sources
per square degree to R=27 mag, with d log N/dm ~ 0.5 in the U band and d log
N/dm ~ 0.3 in the R band. Consistent with these number-magnitude curves,
sources become bluer with increasing magnitude to median U-R=0.6 mag at 24<U<25
mag and U-R=1.2 mag at 25 < R < 26 mag. Because the Lyman break redshifts into
the U band at z~3, at least 1.2x10^5 sources per square degree must be at
redshifts z<3. Measurable U-band fluxes of 73 percent of the 6.3x10^5 sources
per square degree suggest that the majority of these also lie at z < 3. These
results require an enormous space density of objects in any cosmological model.Comment: 17 pages, MNRAS in pres
- …