102 research outputs found
The FRII Broad Line Seyfert 1 Galaxy: PKSJ 1037-2705
In this article, we demonstrate that PKSJ 1037-2705 has a weak accretion flow
luminosity, well below the Seyfert1/QSO dividing line, weak broad emission
lines (BELs) and moderately powerful FRII extended radio emission. It is one of
the few documented examples of a broad-line object in which the time averaged
jet kinetic luminosity, , is larger than the total thermal luminosity
(IR to X-ray) of the accretion flow, . The blazar nucleus dominates
the optical and near ultraviolet emission and is a strong source of hard
X-rays. The strong blazar emission indicates that the relativistic radio jet is
presently active. The implication is that even weakly accreting AGN can create
powerful jets. Kinetically dominated () broad-line objects
provide important constraints on the relationship between the accretion flow
and the jet production mechanism.Comment: To appear in ApJ November 1, 2008, v687n1 issu
Giant radio galaxy 0503-286
Discovery of a giant radio galaxy 0503-286 is reported, based on an ongoing search for such objects using the Ooty-Synthesis Radio Telescope at 327 MHz. Maps are also presented of the source made at 1.4 and 2.7 GHz using the 100-meter Effelsberg Radio Telescope. The source is identified with a 15-mag elliptical at a redshift z = 0.038 and has a classical double radio structure extending over 40 arcmin which corresponds to a linear size of 2.5 Mpc (q0 = 0, H0 = 50 km/s-1 Mpc-1). The pronounced asymmetry of its double structure is probably related to the asymmetric environmental conditions that seem to prevail around the parent galaxy. Some properties related to the radio structure of other known giant radio galaxies are also summarized and discussed
The Evolution of Radio Galaxies at Intermediate Redshift
We describe a new estimate of the radio galaxy 1.4 GHz luminosity function
and its evolution at intermediate redshifts (z~0.4). Photometric redshifts and
color selection have been used to select Bj<23.5 early-type galaxies from the
Panoramic Deep Fields, a multicolor survey of two 25 sq deg fields.
Approximately 230 radio galaxies have then been selected by matching early-type
galaxies with NVSS radio sources brighter than 5 mJy. Estimates of the 1.4 GHz
luminosity function of radio galaxies measure significant evolution over the
observed redshift range. For an Omega_M=1 cosmology the evolution of the radio
power is consistent with luminosity evolution where P(z)=P(0)(1+z)^{k_L} and
3<k_L<5. The observed evolution is similar to that observed for UVX and X-ray
selected AGN and is consistent with the same physical process being responsible
for the optical and radio luminosity evolution of AGN.Comment: 26 pages, 9 Figures, Accepted for Publication in A
Fe II Emission in 14 Low-Redshift Quasars: I - Observations
We present the spectra of 14 quasars with a wide coverage of rest wavelengths
from 1000 to 7300 A. The redshift ranges from z = 0.061 to 0.555 and the
luminosity from M_{B} = -22.69 to -26.32. We describe the procedure of
generating the template spectrum of Fe II line emission from the spectrum of a
narrow-line Seyfert 1 galaxy I Zw 1 that covers two wavelength regions of
2200-3500 A and 4200-5600 A. Our template Fe II spectrum is semi-empirical in
the sense that the synthetic spectrum calculated with the CLOUDY
photoionization code is used to separate the Fe II emission from the Mg II
line. The procedure of measuring the strengths of Fe II emission lines is
twofold; (1) subtracting the continuum components by fitting models of the
power-law and Balmer continua in the continuum windows which are relatively
free from line emissions, and (2) fitting models of the Fe II emission based on
the Fe II template to the continuum-subtracted spectra. From 14 quasars, we
obtained the Fe II fluxes in five wavelength bands, the total flux of Balmer
continuum, and the fluxes of Mg II, Halpha, and other emission lines, together
with the full width at half maxima (FWHMs) of these lines. Regression analysis
was performed by assuming a linear relation between any two of these
quantities. Eight correlations were found with a confidence level higher than
99%. The fact that six of these eight are related to FWHM or M_{BH} may imply
that M_{BH} is a fundamental quantity that controls Gamma or the spectral
energy distribution (SED) of the incident continuum, which in turn controls the
Fe II emission. Furthermore, it is worthy of noting that Fe II(O1)/Fe II(U1) is
found to tightly correlate with Fe II(O1)/Mg II, but not with Fe II(U1)/Mg II.Comment: 50 pages, 10 figures, accepted for publication in Ap
Fertility and gonadal function in female survivors after treatment of early unfavorable Hodgkin lymphoma (HL) within the German Hodgkin Study Group HD14 trial
Background In the HD14 trial, 2× BEACOPPescalated+2× ABVD (2+2) has improved the primary outcome. Compared with 4× ABVD, this benefit might be compromised by more infertility in women. Therefore, we analyzed gonadal function and fertility. Patients and methods Women ≤45 years in ongoing remission at least 1 year after therapy were included. Hormone parameters, menopausal symptoms, measures to preserve fertility, menstrual cycle, pregnancies, and offspring were evaluated. Results Three hundred and thirty one of 579 women addressed participated (57.2%) and 263 per-protocol treated patients qualified (A=ABVD: 137, B=2+2: 126, mean time after therapy 42 and 43 months, respectively). Regular menstrual cycle after treatment (A: 87%, B: 83%) and time to recovery (≤12 months) were not different. Follicle-stimulating hormone and anti-Muellerian hormone were significantly better in arm A. However, pregnancies after therapy favored arm B (A: 15%, B: 26%, P=0.043) and motherhood rates were equivalent to the German normal population. Multivariate analysis revealed prophylactic use of gonadotropin-releasing hormone (GnRH) analogues as highly significant prognostic factor for preservation of fertility (odds ratio=12.87, P=0.001). Severe menopausal symptoms were frequent in women ≥30 years (A: 21%, B: 25%). Conclusions Hormonal levels after 2+2 indicate a reduced ovarian reserve. However, 2+2 in combination with GnRH analogues does not compromise fertility within the evaluated observation tim
GPS radio sources: new optical observations and an updated master list
* Aims. Identify optical counterparts, address uncertain identifications and
measure previously unknown redshifts of the host galaxies of candidate GPS
radio sources, and study their stellar populations. * Methods. Long slit
spectroscopy and deep optical imaging in the B, V and R bands, obtained with
the Very Large Telescope. * Results. We obtain new redshifts for B0316+161,
B0407-658, B0904+039, B1433-040, and identify the optical counterparts of
B0008-421 and B0742+103. We confirm the previous identification for B0316+161,
B0407-658, B0554-026, and B0904+039, and find that the previous identification
for B0914+114 is incorrect. Using updated published radio spectral information
we classify as non GPS the following sources: B0407-658, B0437-454, B1648+015.
The optical colors of typical GPS sources are consistent with single
instantaneous burst stellar population models but do not yield useful
information on age or metallicity. A new master list of GPS sources is
presented.Comment: 10 pages + GPS master list. Accepeted for publication by A&
Radio Frequency Spectra of 388 Bright 74 MHz Sources
As a service to the community, we have compiled radio frequency spectra from
the literature for all sources within the VLA Low Frequency Sky Survey (VLSS)
that are brighter than 15 Jy at 74 MHz. Over 160 references were used to
maximize the amount of spectral data used in the compilation of the spectra,
while also taking care to determine the corrections needed to put the flux
densities from all reference on the same absolute flux density scale. With the
new VLSS data, we are able to vastly improve upon previous efforts to compile
spectra of bright radio sources to frequencies below 100 MHz because (1) the
VLSS flux densities are more reliable than those from some previous low
frequency surveys and (2) the VLSS covers a much larger area of the sky
(declination >-30 deg.) than many other low frequency surveys (e.g., the 8C
survey). In this paper, we discuss how the spectra were constructed and how
parameters quantifying the shapes of the spectra were derived. Both the spectra
and the shape parameters are made available here to assist in the calibration
of observations made with current and future low frequency radio facilities.Comment: Accepted to ApJ
Galaxy Populations and Evolution in Clusters IV: Deep HI Observations of Dwarf Ellipticals in the Virgo Cluster
We present in this paper the deepest Arecibo HI observations of Virgo cluster
dwarf ellipticals (dEs) taken to date. Based on this data we argue that a
significant fraction of Virgo cluster dEs recently underwent evolution. Our new
observations consist of HI 21-cm line observations for 22 classified dE
galaxies with optical radial velocities consistent with membership in the Virgo
cluster. Cluster members VCC 390 and VCC 1713 are detected with HI masses M(HI)
= 6*10^7 M_solar and 8*10^7 M_solar, respectively, while M(HI) in the remaining
20 dE galaxies have upper limits as low as 5*10^5 M_solar. We combine our
results with those for 27 other Virgo cluster dEs with HI observations in the
literature, 7 of which have HI detection claims. New optical images from the
WIYN telescope of 5 of these HI-detected dEs, along with archival data, suggest
that seven of the claimed detections are real, yielding a ~ 15% detection rate.
These HI-detected classified dEs are preferentially located near the periphery
of the Virgo cluster. Three Virgo dEs have observed HI velocity widths > 200
km/s, possibly indicating the presence of a large dark matter content, or
transient extended HI. We discuss the possible origins of these objects and
argue that they originate from field galaxies accreted onto high angular
momentum orbits by Virgo in the last few Gyr. As a result these galaxies are
slowly transformed within the cluster by gradual gas stripping processes,
associated truncation of star formation, and passive fading of stellar
populations. Low-mass early-type cluster galaxies are therefore currently being
produced as the product of cluster environmental effects. We utilize our
results to estimate the recent (past 1-3 Gyr) average mass accretion rate into
the Virgo cluster, finding dM/dt ~ 50 M_solar/year.Comment: Accepted to ApJ, 21 page
Fertility and gonadal function in female survivors after treatment of early unfavorable Hodgkin lymphoma (HL) within the German Hodgkin Study Group HD14 trial
In the HD14 trial, 2Ă—BEACOPPescalated+2Ă—ABVD (2+2) has improved the primary outcome. Compared with 4Ă—ABVD, this benefit might be compromised by more infertility in women. Therefore, we analyzed gonadal function and fertility
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