119495167
The additional line component within the iron Kα profile in MCG -6-30-15: Evidence for blob ejection?
The EPIC data of MCG -6-30-15 observed by XMM-Newton were analyzed for the complexities of the iron Kalpha line. Here we report that the additional line component (ALC) at 6.9 keV undoubtedly appears within the broad iron Kalpha line profile at the high state, whereas it disappears at the low state. These state-dependent behaviors exclude several possible origins and suggest an origin of the ALC in matter being ejected from the vicinity of the black hole. At the low state, the newborn blob ejected from the accretion disk is so Thomson-thick that hard X-rays are blocked from ionizing the old blobs, leading to the disappearance of the ALC. When the blob becomes Thomson-thin as a result of expansion, the hard X-ray will penetrate it and ionize the old ones, emitting the ALC at the high state. The blob ejection is the key to switching the ALC on or off.
119102309
Possible hard X-ray shortages in bursts from KS 1731-260 and 4U 1705-44
Aims. A hard X-ray shortage, implying the cooling of the corona, was observed during bursts of IGR J17473-272, 4U 1636-536, Aql X-1, and GS 1826-238. Apart from these four sources, we investigate here an atoll sample, in which the number of bursts for each source is larger than 5, to explore the possible additional hard X-ray shortage during Rossi X-ray timing explorer (RXTE) era. Methods. According to the source catalog that shows type-I bursts, we analyzed all the available pointing observations of these sources carried out by the RXTE proportional counter array. We grouped and combined the bursts according to their outburst states and searched for the possible hard X-ray shortage while bursting. Results. We found that the island states of KS 1731-260 and 4U 1705-44 show a hard X-ray shortage at significant levels of 4.5 and 4.7σ and a systematic time lag of 0.9 ± 2.1 s and 2.5 ± 2.0 s with respect to the soft X-rays, respectively. While in their banana branches and other sources, we did not find any consistent shortage.
16433217
The afterglows of ultraluminous quasars
Quasars represent a brief phase in the life cycle of most massive galaxies, but the evolutionary connection between central black holes and their host galaxies remains unclear. While quasars are active and shining brighter than the Compton-limit luminosity, their radiation heats the surrounding medium to the Compton temperature, forming Compton spheres extending to the Stromgren radius of Fe26+/He2+. After the quasars shut off, their "afterglow" can be detected through three signatures: (1) an extended X-ray envelope, with a characteristic temperature of ~3 × 107 K, (2) Lyα and Lyβ lines and the K edge of Fe26+, and (3) nebulosity from hydrogen and helium recombination emission lines. We discuss the possibility of detecting these signatures using Chandra, the planned X-Ray Evolving Universe Spectroscopy mission, and ground-based optical telescopes. The luminosity and size of quasar afterglows can be used to constrain the lifetime of quasars.
15715110
Suppressed star formation in circumnuclear regions in seyfert galaxies
Feedback from black hole activity is widely believed to play a key role in regulating star formation and black hole growth. A long-standing issue is the relation between star formation and the fueling of the supermassive black holes in active galactic nuclei (AGNs). We compile a sample of 57 Seyfert galaxies to tackle this issue. We estimate the surface densities of gas and star formation rates in circumnuclear regions (CNRs). Comparing them with the well-known Kennicutt-Schmidt (K-S) law, we find that the star formation rates (SFRs) in the CNRs of most Seyfert galaxies are suppressed in this sample. Feedback is suggested to explain the suppressed SFRs.
17406200
EVOLUTION OF GASEOUS DISK VISCOSITY DRIVEN BY SUPERNOVA EXPLOSIONS IN STAR-FORMING GALAXIES AT HIGH REDSHIFT
Motivated by Genzel et al.'s observations of high-redshift star-forming galaxies, containing clumpy and turbulent rings or disks, we build a set of equations describing the dynamical evolution of gaseous disks with inclusion of star formation and its feedback. Transport of angular momentum is due to "turbulent" viscosity induced by supernova explosions in the star formation region. Analytical solutions of the equations are found for the initial cases of a gaseous ring and the integrated form for a gaseous disk, respectively. For a ring with enough low viscosity, it evolves in a slow process of gaseous diffusion and star formation near the initial radius. For a high viscosity, the ring rapidly diffuses in the early phase. The diffusion drives the ring into a region with a low viscosity and starts the second phase undergoing pile-up of gas at a radius following the decreased viscosity torque. The third is a sharply decreasing phase because of star formation consumption of gas and efficient transportation of gas inward forming a stellar disk. We apply the model to two z similar to 2 galaxies BX 482 and BzK 6004, and find that they are undergoing a decline in their star formation activity.
17396076
INTEGRAL and RXTE/ASM observations on IGR J17098−3628
To probe further the possible nature of the unidentified source IGR J17098-3628, we have carried out a detailed analysis of its long-term time variability as monitored by RXTE/ASM, and of its hard X-ray properties as observed by INTEGRAL. INTEGRAL has monitored this sky region over years and significantly detected IGR J17098-3628 only when the source was in this dubbed active state. In particular, at $\ge$ 20 keV, IBIS/ISGRI caught an outburst in March 2005, lasting for $\sim$5 days with detection significance of 73$\sigma$ (20-40 keV) and with the emission at $ $20 keV) outburst by $\sim$2 days. This resembles the behavior of X-ray novae like XN 1124-683, hence it further suggests a LMXB nature for IGR J17098-3628. While the quality of the ASM data prevents us from drawing any definite conclusions, these discoveries are important clues that, coupled with future observations, will help to resolve the as yet unknown nature of IGR J17098-3628.
119516023
Lattice SU(2) gauge-Higgs system in analytic treatment
The phase diagrams of SU(2) gauge-Higgs model with Higgs field of arbitrary length in the fundamental representation in four and five dimension are studied analytically. A method for determining phase transition lines is proposed. All qualitative features of the phase diagram obtained by Monte Carlo simulations are obtained analytically, and the order of phase transitions can be determined definitely.
11103428
The Broad Fe K-Line Profile in NGC 4151
We present an analysis of the Fe K-line profile of NGC 4151 by using long ASCA observation data obtained in 1995 May. The unprecedented good data quality, which is much better in the energy band around 6.4 keV than that of the famous 4.2 day ASCA observation of MCG -6-30-15 in 1994 July, offers a unique opportunity to study the details of Fe K-line profile. Apart from those characteristics already noticed in earlier ASCA observations on this object (Yaqoob et al.; a broad and skewed profile with a strong peak at about 6.4 keV and a large red wing extending to ~4-5 keV), which is remarkably similar to that of MCG -6-30-15, we also find a weak blue wing extending to about 8 keV, thanks to the good quality of the data. When fitted by a relativistic accretion disk line plus a narrow core at 6.4 keV, the data constrain the accretion disk to be nearly face-on, contrary to the edge-on geometry inferred from optical and UV observations. However, the extended blue wing can not be well fitted even after we include corresponding Fe Kβ components. Ni Kα-line emission by an amount of 12% of Fe Kα is statistically required. An alternative explanation is a model consisting of a narrow core and two disk lines with inclinations of 58° and 0°, respectively. We suppose that the component with inclination of 58° was observed directly, consistent with its edge-on geometry, and the component with inclination of 0° was scattered into our line of sight by a Compton mirror, which might be the cool accretion disk corona proposed by Poutanen et al.
18156072
The Unique Rapid Variabilities of the Iron Kα Line Profiles in NGC 4151
We present a detailed analysis of iron Kα line variabilities in NGC 4151 using long ASCA observation data obtained in 1995 May. Despite the relatively small amplitude variations in the continuum flux, the iron Kα line flux and profile show dramatic variations. Particularly, the line profile changes from a single peak to what appears to be double peaks and back in timescales of a few times 104 s. The apparently double-peaked profiles can be well interpreted as line emission from a Keplerian ring around a massive black hole. An absorption line at around 5.9 keV is also marginally detected. We discuss current Fe K line models, but none of them can well explain the observed line and continuum variations.
13951142
The Chandra Carina Complex Project View of Trumpler 16
Trumpler 16 is a well-known rich star cluster containing the eruptive supergiant ? Carinae and located in the Carina star-forming complex. In the context of the Chandra Carina Complex Project, we study Trumpler 16 using new and archival X-ray data. A revised X-ray source list of the Trumpler 16 region contains 1232 X-ray sources including 1187 likely Carina members. These are matched to 1047 near-infrared counterparts detected by the HAWK-I instrument at the Very Large Telescope allowing for better selection of cluster members. The cluster is irregular in shape. Although it is roughly circular, there is a high degree of sub-clustering, with no noticeable central concentration and an extension to the southeast. The high-mass stars show neither evidence of mass segregation nor evidence of strong differential extinction. The derived power-law slope of the X-ray luminosity function for Trumpler 16 reveals a much steeper function than the Orion Nebula Cluster, implying a different ratio of solar- to higher-mass stars. We estimate the total Trumpler 16 pre-main-sequence population to be >6500 Class II and Class III X-ray sources. An overall K-excess disk frequency of ~8.9% is derived using the X-ray-selected sample, although there is some variation among the sub-clusters, especially in the southeastern extension. X-ray emission is detected from 29 high-mass stars with spectral types between B2 and O3.
37044521
Multiplicity and transverse momentum dependence of two- and four-particle correlations in pPb and PbPb collisions
Measurements of two- and four-particle angular correlations for charged particles emitted in pPb collisions are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 31 nb^(−1), were collected during the 2013 LHC pPb run at a nucleon–nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. The results are compared to 2.76 TeV semi-peripheral PbPb collision data, collected during the 2011 PbPb run, covering a similar range of particle multiplicities. The observed correlations are characterized by the near-side (|Δϕ|≈0) associated pair yields and the azimuthal anisotropy Fourier harmonics (v_n). The second-order (v_2) and third-order (v_3) anisotropy harmonics are extracted using the two-particle azimuthal correlation technique. A four-particle correlation method is also applied to obtain the value of v_2 and further explore the multi-particle nature of the correlations. Both associated pair yields and anisotropy harmonics are studied as a function of particle multiplicity and transverse momentum. The associated pair yields, the four-particle v_2, and the v_3 become apparent at about the same multiplicity. A remarkable similarity in the v_3 signal as a function of multiplicity is observed between the pPb and PbPb systems. Predictions based on the color glass condensate and hydrodynamic models are compared to the experimental results.