11,285 research outputs found
Field Theory of Disordered Elastic Interfaces at 3-Loop Order: Critical Exponents and Scaling Functions
For disordered elastic manifolds in the ground state (equilibrium) we obtain
the critical exponents for the roughness and the correction-to-scaling up to
3-loop order, i.e. third order in , where is the internal
dimension . We also give the full 2-point function up to order
, i.e. at 2-loop order.Comment: v1: 74 pages, 88 figures; v2: paper split into to parts; v3: typos
corrected and hyper-ref enable
Incommensurate nematic fluctuations in the two-dimensional Hubbard model
We analyze effective d-wave interactions in the two-dimensional extended
Hubbard model at weak coupling and small to moderate doping. The interactions
are computed from a renormalization group flow. Attractive d-wave interactions
are generated via antiferromagnetic spin fluctuations in the pairing and charge
channels. Above Van Hove filling, the d-wave charge interaction is maximal at
incommensurate diagonal wave vectors, corresponding to nematic fluctuations
with a diagonal modulation. Below Van Hove filling a modulation along the
crystal axes can be favored. The nematic fluctuations are enhanced by the
nearest-neighbor interaction in the extended Hubbard model, but they always
remain smaller than the dominant antiferromagnetic, pairing, or charge density
wave fluctuations.Comment: 8 pages, 4 figures; figures improve
Charm and Beauty Production at HERA-B
The HERA-B experiment at DESY has acquired a data set of approximately
300,000 decays J/psi -> l+l- during its 2002/2003 data-taking period. These
data are used to analyze the production of heavy quarks in proton-nucleus
interactions at a center-of-mass energy of 41.6 GeV.
In this article, preliminary results of two measurements are discussed, a
measurement of nuclear effects in the production of J/psi mesons and a
measurement of the b-bbar production cross section.Comment: 4 pages, 3 figures, to appear in Proc. XIII International Workshop on
Deep Inelastic Scattering (DIS2005), April 27 - May 1, 2005, Madison,
Wisconsi
The low-metallicity QSO HE 2158-0107: A massive galaxy growing by the accretion of nearly pristine gas from its environment?
[abridged] The metallicities of AGN are usually well above solar in their
NLR, often reaching up to several times solar in their broad-line regions.
Low-metallicity AGN are rare objects which have so far always been associated
with low-mass galaxies hosting low-mass BHs (M_BH<10^6Msun). In this paper we
present IFS data of the low-redshift QSO HE 2158-0107 for which we find strong
evidence for sub-solar NLR metallicities associated with a massive BH
(M_BH~3x10^8Msun). The QSO is surrounded by a large extended emission-line
region reaching out to 30kpc from the QSO in a tail-like geometry. We present
optical and near-IR images and investigate the properties of the host galaxy.
The SED of the host is rather blue, indicative of a significant young age
stellar population formed within the last 1Gyr. A 3sigma upper limit of
L_bulge<4.5x10^10Lsun for the H band luminosity and a corresponding stellar
mass upper limit of M_bulge<3.4x10^10Msun show that the host is offset from the
local BH-bulge relations. This is independently supported by the kinematics of
the gas. Although the stellar mass of the host galaxy is lower than expected,
it cannot explain the exceptionally low metallicity of the gas. We suggest that
the extended emission-line region and the galaxy growth are caused by the
infall of nearly pristine gas from the environment of the QSO host. Minor
mergers of dwarf galaxies or the theoretically predicted smooth accretion of
cold gas are both potential drivers behind that process. Since the metallicity
of the gas in the NLR is much lower than expected, we suspect that the external
gas has already reached the galaxy centre and may even contribute to the
current feeding of the BH. HE 2158-0107 appears to represent a particular phase
of substantial BH and galaxy growth that can be observationally linked with the
accretion of external material from its environment.Comment: 14 pages, 12 figures, accepted for publication in A&
Field Theory of Disordered Elastic Interfaces at 3-Loop Order: The -Function
We calculate the effective action for disordered elastic manifolds in the
ground state (equilibrium) up to 3-loop order. This yields the
renormalization-group -function to third order in , in an
expansion in the dimension around the upper critical dimension . The
calculations are performed using exact RG, and several other techniques, which
allow us to resolve consistently the problems associated with the cusp of the
renormalized disorder.Comment: This is the first part of arXiv:1707.09802v1. The remaining part is
in arXiv:1707.09802v2. 47 pages, 67 figures. v2: typos corrected and
hyper-ref enable
The properties of the extended warm ionised gas around low-redshift QSOs and the lack of extended high-velocity outflows
(Abridged) We present a detailed analysis of a large sample of 31
low-redshift, mostly radio-quiet type 1 QSOs observed with integral field
spectroscopy to study their extended emission-line regions (EELRs). We focus on
the ionisation state of the gas, size and luminosity of extended narrow line
regions (ENLRs), which corresponds to those parts of the EELR dominated by
ionisation from the QSO, as well as the kinematics of the ionised gas. We
detect EELRs around 19 of our 31 QSOs (61%) after deblending the unresolved QSO
emission and the extended host galaxy light in the integral field data. We
identify 13 EELRs to be entirely ionised by the QSO radiation, 3 EELRs are
composed of HII regions and 3 EELRs display signatures of both ionisation
mechanisms at different locations. The typical size of the ENLR is 10kpc at a
median nuclear [OIII] luminosity of log(L([OIII])/[erg/s])=42.7+-0.15. We show
that the ENLR sizes are least a factor of 2 larger than determined with HST,
but are consistent with those of recently reported type 2 QSOs at matching
[OIII] luminosities. The ENLR of type 1 and type 2 QSOs appear to follow the
same size-luminosity relation. Furthermore, we show for the first time that the
ENLR size is much better correlated with the QSO continuum luminosity than with
the total/nuclear [OIII] luminosity. We show that ENLR luminosity and radio
luminosity are correlated, and argue that radio jets even in radio-quiet QSOs
are important for shaping the properties of the ENLR. Strikingly, the
kinematics of the ionised gas is quiescent and likely gravitationally driven in
the majority of cases and we find only 3 objects with radial gas velocities
exceeding 400km/s in specific regions of the EELR that can be associate with
radio jets. In general, these are significantly lower outflow velocities and
detection rates compared to starburst galaxies or radio-loud QSOs.Comment: 34 page, 22 figures (slightly degraded in resolution), 10 tables,
accepted for publication in A&A, minor corrections to match with the
publisher versio
The spatial clustering of ROSAT All-Sky Survey Active Galactic Nuclei IV. More massive black holes reside in more massive dark matter halos
This is the fourth paper in a series that reports on our investigation of the
clustering properties of active galactic nuclei (AGN) identified in the ROSAT
All-Sky Survey (RASS) and Sloan Digital Sky Survey (SDSS). In this paper we
investigate the cause of the X-ray luminosity dependence of the clustering of
broad-line, luminous AGN at 0.16<z<0.36. We fit the H-alpha line profile in the
SDSS spectra for all X-ray and optically-selected broad-line AGN, determine the
mass of the super-massive black hole (SMBH), M_BH, and infer the accretion rate
relative to Eddington (L/L_EDD). Since M_BH and L/L_EDD are correlated, we
create AGN subsamples in one parameter while maintaining the same distribution
in the other parameter. In both the X-ray and optically-selected AGN samples we
detect a weak clustering dependence with M_BH and no statistically significant
dependence on L/L_EDD. We find a difference of up to 2.7sigma when comparing
the objects that belong to the 30% least and 30% most massive M_BH subsamples,
in that luminous broad-line AGN with more massive black holes reside in more
massive parent dark matter halos at these redshifts. These results provide
evidence that higher accretion rates in AGN do not necessarily require dense
galaxy environments in which more galaxy mergers and interactions are expected
to channel large amounts of gas onto the SMBH. We also present semi-analytic
models which predict a positive M_DMH dependence on M_BH, which is most
prominent at M_BH ~ 10^{8-9} M_SUN.Comment: 24 pages, 16 figures, 2015 ApJ, 815, 2
Integral field spectroscopy of nearby QSOs: I. ENLR size-luminosity relation, ongoing star formation & resolved gas-phase metallicities
[abridged] We present optical integral field spectroscopy for a flux-limited
sample of 19 QSOs at z<0.2 and spatially resolve their ionized gas properties
at a physical resolution of 2-5kpc. The extended narrow line regions (ENLRs),
photoionized by the radiation of AGN, have sizes of up to several kpc and
correlate more strongly with the QSO continuum luminosity than with the
integrated [OIII] luminosity. We find a relation of the form
log(r)~(0.46+-0.04)log(L_5100), reinforcing the picture of an approximately
constant ionization parameter for the ionized clouds across the ENLR. Besides
the ENLR, we also find gas ionized by young massive stars in more than 50 per
cent of the galaxies on kpc scales. In more than half of the sample, the
specific star formation rates based on the extinction-corrected Ha luminosity
are consistent with those of inactive disc-dominated galaxies, even for some
bulge-dominated QSO hosts. Enhanced SFRs of up to 70Msun/yr are rare and always
associated with signatures of major mergers. Comparison with the SFR based on
the 60+100micron FIR luminosity suggests that the FIR luminosity is
systematically contaminated by AGN emission and Ha appears to be a more robust
and sensitive tracer for the star formation rate. Evidence for efficient AGN
feedback is scarce in our sample, but some of our QSO hosts lack signatures of
ongoing star formation leading to a reduced specific SFR with respect to the
main sequence of galaxies. Based on 12 QSOs where we can make measurements, we
find that on average bulge-dominated QSO host galaxies tend to fall below the
mass-metallicity relation compared to their disc-dominated counterparts. While
not yet statistically significant for our small sample, this may provide a
useful diagnostic for future large surveys if this metal dilution can be shown
to be linked to recent or ongoing galaxy interactions.Comment: 30 pages, 16 figures, 6 tables, accepted for publication in MNRA
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