28 research outputs found
FeII/MgII Emission Line Ratios of QSOs. II. z>6 Objects
Near-infrared spectra of four QSOs located at are obtained with the
OH-airglow suppressor mounted on the Subaru telescope. The FeII/MgII
emission-line ratios of these QSOs are examined by the same fitting algorithm
as in our previous study of QSOs. The fitting results show that two out
of the four QSOs have significant FeII emission in their rest-UV spectra,
while the other two have almost no FeII features. We also applied our fitting
algorithm to more than 10,000 SDSS QSOs and found two trends in the
distribution of FeII/MgII against redshift: (1) the upper envelope of the
FeII/MgII distribution at shows a probable declination toward high
redshift, and (2) the median distribution settles into lower ratios at with small scatter compared to the other redshift. We discuss an Fe/Mg
abundance evolution of QSOs with a substantial contribution from the diverse
nature of the broad-line regions in high-redshift QSOs.Comment: 12 pages, 2 figures. Accepted for publication in ApJ (10 October
2004, v614
Nature of a Strongly-Lensed Submillimeter Galaxy SMM J14011+0252
We have carried out near-infrared JHK spectroscopy of a gravitationally
lensed submillimeter galaxy SMM J14011+0252 at z=2.565, using OHS and CISCO on
the Subaru telescope. This object consists of two optical components, J1 and
J2, which are lensed by the cluster Abell 1835. J1 suffers additional strong
lensing by a foreground galaxy at z=0.25 in the cluster. The rest-optical
H-alpha, H-beta, and [O II]3727 lines are detected in both J1 and J2, and [N
II]6548,6583 lines are also detected in J1. A diagnosis of emission-line ratios
shows that the excitation source of J1 is stellar origin, consistent with
previous X-ray observations. The continua of J1 and J2 show breaks at rest
4000A, indicating relatively young age. Combined with optical photometry, we
have carried out model spectrum fitting of J2 and find that it is a very young
(~50 Myr) galaxy of rather small mass (~10e8 M_sol) which suffers some amount
of dust extinction. A new gravitational lensing model is constructed to assess
both magnification factor and contamination from the lensing galaxy of the
component J1, using HST-F702W image. We have found that J1 suffers strong
lensing with magnification of ~30, and its stellar mass is estimated to be <
10e9 M_sol. These results suggest that SMM J14011+0252 is a major merger system
at high redshift that undergoes intense star formation, but not a formation
site of a giant elliptical. Still having plenty of gas, it will transform most
of the gas into stars and will evolve into a galaxy of < 10e10 M_sol.
Therefore, this system is possibly an ancestor of a less massive galaxy such as
a mid-sized elliptical or a spiral at the present.Comment: 21 pages, 11 figures. Accepted for publication in Astronomical
Journa
Infrared Spectroscopy of 15 Radio Galaxies at 2<z<2.6
Near-infrared spectra of 15 high-redshift radio galaxies (HzRGs) located at
were obtained by the OH Airglow Suppressor spectrograph mounted on
the Subaru telescope. The UV-optical line ratio diagnostic diagrams indicate
that half of the observed HzRGs have extended emission-line regions with low
metal abundance, photoionized by a flat-continuum active galactic nucleus such
as a quasar. We also found two probable correlations between radio and
rest-optical parameters: (1) HzRGs with massive hosts tend to have a redder
rest-optical continuum, and (2) HzRGs with smaller radio sizes also show a
redder optical continuum. On the basis of the correlations, the nature of HzRGs
at is discussed.Comment: 23 pages, 7 figures, Corrected typos and style. Accepted for
publication in ApJ (November 20, 2003
Economic profits enhance trust, perceived integrity and memory of fairness in interpersonal judgment.
Does money lead to trust in personality and intention of others? Humans have a strong tendency to judge the intention of others from their sequent behaviors. In general, people trust others who behave fairly, but not always. Here we show that judgments of both intentional aspects and memory of intentional behavior are automatically influenced by unintentional benefits from the behaviors of others. We conducted a reward-manipulated and repeated trust game by using real participants interacting with moving image partners on a computer screen. The participants assessed likability, trustworthiness, and perceived integrity of the partners in pre- and post-game questionnaires. The results of judgments of all three dimensions and the memory of frequency of each partner's fair behavior (sharing) were strongly influenced by profitability in the trust game, even though all partners shared 75% of the profit and participants were told that profitability was randomly assigned to each partner. Furthermore, these effects were moderated by the gender of the participants: males were more sensitive to monetary profits than were females. The results reveal that humans automatically trust, approve the integrity of, and recall well the fair behavior of others who provide affectively positive outcomes such as monetary profits. We call this phenomenon the "affect ripple effect"
Percentages of high-risk investment (30 UEC) of male and female participants over all trust games. Graphs show the mean ± SEM.
<p>Percentages of high-risk investment (30 UEC) of male and female participants over all trust games. Graphs show the mean ± SEM.</p
Experimental design of trust game.
<p>A trial in the game was divided into a decision phase and an outcome phase and was played with moving image partners. During the decision phase, the chosen option by participants was required within 2.5 s after the start of the trial. The parson depicted in the photograph has given written informed consent, as outlined in the PLoS consent form, to publication of his photograph.</p
Experimental design of partner judgments.
<p>(A) The scale for likability and trustworthiness. (B) The scale for perceived integrity. The parson depicted in the photograph has given written informed consent, as outlined in the PLoS consent form, to publication of his photograph.</p