684 research outputs found
A sub-kpc-scale binary AGN with double narrow-line regions
We present the kinematic properties of a type-2 QSO, SDSS J132323.33-015941.9
at z~0.35, based on the analysis of Very Large Telescope integral field
spectroscopy and Hubble Space Telescope (HST) imaging, which suggest that the
target is a binary active galactic nucleus (AGN) with double narrow-line
regions. The QSO features double-peaked emission lines ([OIII] and Hb) which
can be decomposed into two kinematic components. The flux-weighted centroids of
the blue and red components are separated by ~0.2" (0.8 kpc in projection) and
coincide with the location of the two stellar cores detected in the HST
broad-band images, implying that both stellar cores host an active black hole.
The line-of-sight velocity of the blue component is comparable to the
luminosity-weighted velocity of stars in the host galaxy while the red
component is redshifted by ~240 km/s, consistent with typical velocity offsets
of two cores in a late stage of a galaxy merger. If confirmed, the target is
one of the rare cases of sub-kpc scale binary AGNs, providing a test-bed for
understanding the binary AGN population.Comment: 5 pages, 3 figure
The 750 GeV Diphoton Excess May Not Imply a 750 GeV Resonance
We discuss non-standard interpretations of the 750 GeV diphoton excess
recently reported by the ATLAS and CMS Collaborations which do not involve a
new, relatively broad, resonance with a mass near 750 GeV. Instead, we consider
the sequential cascade decay of a much heavier, possibly quite narrow,
resonance into two photons along with one or more invisible particles. The
resulting diphoton invariant mass signal is generically rather broad, as
suggested by the data. We examine three specific event topologies - the antler,
the sandwich, and the 2-step cascade decay, and show that they all can provide
a good fit to the observed published data. In each case, we delineate the
preferred mass parameter space selected by the best fit. In spite of the
presence of invisible particles in the final state, the measured missing
transverse energy is moderate, due to its anti- correlation with the diphoton
invariant mass. We comment on the future prospects of discriminating with
higher statistics between our scenarios, as well as from more conventional
interpretations.Comment: Discussion about the ATLAS Moriond EW2016 added. Matched to PRL
accepted versio
Calibrating CIV-based black hole mass estimators
We present the single-epoch black hole mass estimators based on the CIV (1549
A) broad emission line, using the updated sample of the reverberation-mapped
AGNs and high-quality UV spectra. By performing multi-component spectral
fitting analysis, we measure the CIV line widths (FWHM_CIV) and line dispersion
(sigma_CIV) and the continuum luminosity at 1350 A (L_1350) to calibrate the
CIV-based mass estimators. By comparing with the Hbeta reverberation-based
masses, we provide new mass estimators with the best-fit relationships, i.e.,
M_BH \propto L_1350 ^ (0.50+-0.07) sigma_CIV ^2 and M_BH \propto L_1350 ^
(0.52+-0.09) FWHM_CIV ^ (0.56+-0.48). The new CIV-based mass estimators show
significant mass-dependent systematic difference compared to the estimators
commonly used in the literature. Using the published Sloan Digital Sky Survey
QSO catalog, we show that the black hole mass of high-redshift QSOs decreases
on average by ~0.25 dex if our recipe is adopted.Comment: 12 pages, 7 figures, ApJ in press, figure revise
Modeling reverberation mapping data II: dynamical modeling of the Lick AGN Monitoring Project 2008 dataset
We present dynamical modeling of the broad line region (BLR) for a sample of
five Seyfert 1 galaxies using reverberation mapping data taken by the Lick AGN
Monitoring Project in 2008. By modeling the AGN continuum light curve and
H line profiles directly we are able to constrain the geometry and
kinematics of the BLR and make a measurement of the black hole mass that does
not depend upon the virial factor, , needed in traditional reverberation
mapping analysis. We find that the geometry of the BLR is generally a thick
disk viewed close to face-on. While the H emission is found to come
preferentially from the far side of the BLR, the mean size of the BLR is
consistent with the lags measured with cross-correlation analysis. The BLR
kinematics are found to be consistent with either inflowing motions or
elliptical orbits, often with some combination of the two. We measure black
hole masses of for Arp
151, for Mrk 1310, for NGC 5548,
for NGC 6814, and for SBS
1116+583A. The factors measured individually for each AGN are found to
correlate with inclination angle, although not with , ,
or FWHM/ of the emission line profile.Comment: 21 pages, 24 figures, 3 tables, Accepted for publication in MNRAS,
corrected masses for NGC 5548 and NGC 6814 in the abstrac
?????? ??? ????????? ???????????? ????????? ?????? ?????? ????????? ?????? ??????
????????? ????????? ????????? ?????? ????????? ????????? ??????????????? ????????? ??? ?????? ???????????? ?????? ??????????????? ?????? ????????? ?????? ??????. ????????? ????????? ??????????????? ?????? ????????? ???????????? ???????????? ?????? ????????? ?????? ?????? ????????? ???????????? ?????????, ?????? ??? ??????(O&M, Operation and Management) ??????????????? ????????? ????????? ?????? ??? ??????????????? ????????? ?????? ??????????????? ???????????? ??????. ????????? ????????? ?????? ?????? ?????? ??? ?????? ?????? ???, ?????? ??????????????? ????????? ???????????? ????????? ?????? ???????????? ???????????? ?????????, ???????????? ??????????????? ?????? ????????? ??? ?????? ????????? ??? ??? ??????. ????????? ?????? ??????????????? ?????? ???????????? ?????? ????????? ????????? ????????? ??????????????? ?????????????????? ?????? ???????????? ?????????. ????????? ??? ??????????????? (1) ????????? ???????????? ?????? ???????????? ????????? ???????????? ??????????????? ????????? ???????????? ????????? ????????????, (2) ????????? ????????? ????????? ???????????? ?????? NREL 5 MW??? ?????? ????????? ???????????? ???????????? ???, ???????????? ?????? ?????? ??? ?????? ???????????? ?????? ?????? ????????? ???????????? ??????????????????, ?????? ?????? ????????? ?????? ???????????? ????????? ???????????????.ope
Efficient hematite photoanodes prepared by hydrochloric acid-treated solutions with amphiphilic graft copolymer
Simple and low-cost approaches for the preparation of photoelectrodes are crucial to enable a transition towards a sustainable and circular economy in which sunlight energy is efficiently harnessed and used. Here, a novel and simple process is presented to prepare a sol solution that can be cast by spin coating deposition for mesoporous α-Fe2O3 hematite water-splitting photoanodes, reaching 1.05 mA cm−2 at 1.23 VRHE under 1 sun illumination. The sol solution is prepared using inexpensive commercial ∼10 nm α-Fe2O3 hematite nanoparticles as hematite film precursor, an amphiphilic poly(vinyl chloride)-graft-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer as a pore template, and HCl acid as an iron oxide phase directing agent. The hydrophilic POEM side chains selectively interact with HCl-treated hematite nanoparticles allowing their dispersion. Moreover, the HCl in the sol solution disperses and dissolves the hematite nanoparticles which re-precipitate as mixed phase γ-FeOOH and β-FeOOH, leading to better performant hematite films due to finer nanostructures, a more pronounced hematite (110) plane, and a more hydroxylated surface. This work demonstrates that synergies between an amphiphilic graft copolymer, hematite nanoparticles and HCl acid can be exploited in the inexpensive spin coating technique to prepare robust, stable and promising hematite photoanodes for energy devices.</p
- …