16169950
P CYGNI PROFILES OF MOLECULAR LINES TOWARD ARP 220 NUCLEI
We report ~100 pc (0farcs3) resolution observations of (sub)millimeter HCO+ and CO lines in the ultraluminous infrared galaxy Arp 220. The lines peak at two merger nuclei, with HCO+ being more spatially concentrated than CO. Asymmetric line profiles with blueshifted absorption and redshifted emission are discovered in HCO+(3-2) and (4-3) toward the two nuclei and in CO(3-2) toward one nucleus. We suggest that these P Cygni profiles are due to ~100 km s–1 outward motion of molecular gas from the nuclei. This gas is most likely outflowing from the inner regions of the two nuclear disks rotating around individual nuclei, clearing the shroud around the luminosity sources there.
8320136
CAVITY OF MOLECULAR GAS ASSOCIATED WITH SUPERNOVA REMNANT 3C 397
3C 397 is a radio and X-ray bright Galactic supernova remnant (SNR) with an unusual rectangular morphology. Our CO observation obtained with the Purple Mountain Observatory at Delingha, Qinghai Province, China reveals that the remnant is well confined in a cavity of molecular gas and embedded at the edge of a molecular cloud (MC) at the local standard of rest systemic velocity of similar to 32 km s(-1). The cloud has a column density gradient increasing from southeast to northwest, perpendicular to the Galactic plane, in agreement with the elongation direction of the remnant. This systemic velocity places the cloud and SNR 3C 397 at a kinematic distance of similar to 10.3 kpc. The derived mean molecular density (similar to 10-30 cm(-3)) explains the high volume emission measure of the X-ray emitting gas. A (12)CO line broadening of the similar to 32 km s(-1) component is detected at the westmost boundary of the remnant, which provides direct evidence of the SNR MC interaction and suggests multi-component gas there with dense (similar to 10(4) cm(-3)) molecular clumps. We confirm the previous detection of an MC at similar to 38 km s(-1) to the west and south of the SNR and argue, based on H I self-absorption, that the cloud is located in the foreground of the remnant. A list of Galactic SNRs presently known and suggested to be in physical contact with environmental MCs is appended in this paper.
119234828
CS 5-4 survey toward nearby IR bright galaxies
With the observations of the CS 5-4 line toward a sample of 24 infrared bright galaxies using HHSMT, we detected CS 5-4 emission in 14 galaxies, including 12 ULIRGs/LIRGs and 2 nearby normal galaxies. As a good dense gas tracer, which has been well used for studying star formation in the Milky Way, CS 5-4 can trace the active star forming gas in galaxies. The correlation between CS 5-4 luminosity, which is estimated with detected CS 5-4 line emission, and infrared luminosity in these 14 galaxies is fitted with correlation coefficient of 0.939 and the slope close to unity. This correlation confirmed that dense gas, which is closely linked to star formation, is very important for understanding star formation in galaxies.
118415484
UNVEILING THE PHYSICAL PROPERTIES AND KINEMATICS OF MOLECULAR GAS IN THE ANTENNAE GALAXIES (NGC 4038/9) THROUGH HIGH-RESOLUTION CO (J=3-2) OBSERVATIONS
We present a similar to 1 '' (100 pc) resolution (CO)-C-12 (3-2) map of the nearby intermediate-stage interacting galaxy pair NGC 4038/9 (the Antennae galaxies) obtained with the Submillimeter Array. We find that half the CO (3-2) emission originates in the overlap region where most of the tidally induced star formation had been previously found in shorter wavelength images, with the rest being centered on each of the nuclei. The gross distribution is consistent with lower resolution single-dish images, but we show for the first time the detailed distribution of the warm and dense molecular gas across this galaxy pair at resolutions comparable to the size of a typical giant molecular complex. While we find that 58% (33/57) of the spatially resolved Giant Molecular Associations (a few x 100 pc) are located in the overlap region, only <= 30% spatially coincides with the optically detected star clusters, suggesting that the bulk of the CO (3-2) emission traces the regions with very recent or near future star formation activity. The spatial distribution of the CO (3-2)/CO (1-0) integrated brightness temperature ratios mainly ranges between 0.3 and 0.6, which suggests that on average the CO (3-2) line in the Antennae is not completely thermalized and similar to the average values of nearby spirals. A higher ratio is seen in both nuclei and the southern complexes in the overlap region. A higher radiation field associated with intense star formation can account for the nucleus of NGC 4038 and the overlap region, but the nuclear region of NGC 4039 shows relatively little star formation or active galactic nucleus activity and cannot be easily explained. We show kinematical evidence that the high line ratio in NGC 4039 is possibly caused by gas inflow into the counter-rotating central disk.
118506676
CO observation of SNR IC 443
We present our 12CO and 13CO mapping observations of SNR IC 443 interacting with molecular clouds. It is the first large-scale high-resolution 13CO mapping observation in the surrounding region. The morphologies of IC 443 in 12CO and 13CO are compared with the optical, infrared, Spitzer far-infrared, X-ray, and neutral atomic gas (HI). We also make comparison and analysis in the kinematics, using the date-cubes of 12CO, 13CO and HI, to help distinguish the complicated gas motions in the shocked regions. Based on the work of Wang & Scoville (1992), we present a new model to explain the coexistence of multiple shocks with different speeds in a pc-scale region at the central clump B. We test this new model by analyzing the HI and CO distribution in both velocity and space domain. We also establish the relationship between the dissociation rate of shocked molecular gas and the shock velocity in this region. Finally, we derive the optical depth of 12CO with the 13CO spectra in clump B, and discuss the validity of the assumption of optically thin emission for the shocked 12CO.
119287240
Searches for Majorana neutrinos in $B^-$ decays
Searches for heavy Majorana neutrinos in B- decays in final states containing hadrons plus a \mu- \mu- pair have been performed using 0.41/fb of data collected with the LHCb detector in proton-proton collisions at a center-of-mass energy of 7 TeV. The D+ \mu- \mu- and D*+ \mu- \mu- final states can arise from the presence of virtual Majorana neutrinos of any mass. Other final states containing \pi+, Ds+, or D0\pi+ can be mediated by an on-shell Majorana neutrino. No signals are found and upper limits are set on Majorana neutrino production as a function of mass, and also on the B- decay branching fractions.
34494584
Measurement of the electroweak penguin process B-->X(s)l+l-.
We report the first measurement of the branching fraction for the inclusive decay B-->X(s)l(+)l(-), where l is either an electron or a muon, and X(s) is a hadronic recoil system that contains an s quark. We analyzed a data sample of 65.4 x 10(6) B meson pairs collected with the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. We find B(B-->X(s)l(+)l(-))=[6.1 +/-1.4(stat) +1.4-1.1(syst)] x 10(-6) for dilepton masses greater than 0.2 GeV/c(2).
102339817
BUNCH-BY-BUNCH ONLINE DIAGNOSTICS AT HLS
The design goal for the bunch-by-bunch analogue transverse feedback system at the Hefei Light Source (HLS) is to cure the transverse coupled bunch instabilities. The prototype implemented bunch-by-bunch feedback in 2006. Then we changed the circuit and replaced some components by ones of higher performance in order to get better effect. Diagnostic techniques are important tools to determine instabilities and to confirm the performance of the feedback systems. In addition to transverse feedback this system can provide online beam diagnostics and analysis in transverse and longitudinal directions. The diagnostic functions can record the response of every bunch while the feedback system manipulates the beam. The experimental results are presented. INTRODUCTION The HLS is a facility dedicated to synchrotron radiation. Its electron storage ring, with a circumference of 66 meters, operates with 45 bunches in 204.035MHz Radio Frequency (RF), and contains 31 BPMs. Each BPM has a four-button type pick-ups mounted in a skew of 45°. A 200MeV injection beam from linac and transport line ramps to 800MeV and operates at 200300mA in the HLS storage ring. A multi-cycle multi-turn injection system is used for current accumulation. A wiggler is available in the HLS. There are three operating states: injection (200MeV), 800MeV Optics-Normal, and 800MeV Optics-Wiggler. A bunch-by-bunch transverse feedback system has been under commissioning at HLS, and it is introduced in this paper. The transverse prototype implemented bunchby-bunch feedback in 2006. In order to get better effect, then we replaced some components by ones of higher performance, such as the strip line feedback kicker, the optical fibre notch filter. We moved the 3-tap filter in front of the hybrid network and add DC offset in the circuit to gain better signal to noise ratio. In addition to transverse feedback this system can provide online beam diagnostics and analysis in transverse and longitudinal directions. The diagnostic functions can record the response of every bunch while the feedback system manipulates the beam. Some phenomena observed are presented, as well as the feedback experimental results. THE FEEDBACK SYSTEM Prototype The bunch-by-bunch analogue transverse feedback system at HLS consists of 2 signal detectors (pickups), a RF front-end, a signal processing, a frequency doubling circuit, a vectors operation and control module, 2 Notch Filters, 4 RF amplifiers and a kicker. An overview of it is in [1]. We use double balance mixers (DBM) to substitute for the attenuators and phase shifters. This new method can simplify the system. It supports a range of 360 degree phase adjusting the feedback signal by vector computation. The signal can be controlled as either a feedback signal or an exciting signal arbitrarily. In order to test the prototype serial experiments were performed on timing, phasing, and powering of the feedback signal with the old 73cm general kicker. This system also works well in 800MeV operation [1].
14896531
Strong Ca II Absorption Lines in the Reddened Quasar SDSS J2339–0912: Evidence of the Collision/Merger in the Host Galaxy?
We report the detection of strong Ca II/Mg II absorption lines at the quasar redshift in the narrow-line quasar SDSS J2339-0912 (z = 0.6604). The quasar exhibits strong Fe II, a small Balmer emission line width, and a very red B - Ks color. Both the optical continuum and broad emission lines are reddened by SMC-like dust of E(B - V) 1.0 mag, while its near-infrared color (J - Ks = 1.60) shows little reddening. The Ca II absorption lines are saturated and resolved with an FWHM of 362 km s-1 and an equivalent width of W = 4.2 A (in the source rest frame). Mg II absorption lines are also saturated and have a similar line width. The line profile and the fact that there is no evidence of starlight from the host galaxy suggest that these absorption lines are not of a stellar origin. The ratio of column density of Ca II to that of dust is consistent with that of the interstellar medium (ISM) in our Galaxy. We suggest that both the heavy reddening and the large absorption line width are due to the highly disturbed ISM on the line of sight toward the quasar and that the disturbance is caused by a galaxy collision or even merger in the quasar host galaxy.
118090697
Two Compton-Thick Active Nuclei in Arp 220?
Narrow-band spectral imaging with sub-pixel resolution of the Chandra-ACIS archival observation of the ULIRG merger Arp 220 strongly suggests two Compton thick nuclei, spatially coincident with the infrared and radio emitting nuclear clusters, and separated by 1" (~ 365 pc at a distance of 76 Mpc). These previously undetected highly obscured AGNs - West (W) and East (E) - are imaged, and separated from neighboring sources, in the 6-7 keV band, where the Fe-K lines dominate the emission. The western nucleus is also detected at energies above 7 keV. We estimate Fe-K equivalent width ~ 1 keV or possibly greater for both sources, and observed 2-10 keV luminosities L_X < 3.2 x 10^40 erg/s (W) and <1.3 x 10^40 erg/s (E). From the observed Fe-K lines luminosities{, and assuming on the basis of the XMM-Newton spectrum that 40% of this may be from the 6.4 keV component, we evaluate 2-10 keV intrinsic luminosities L_X ~ 1 x 10^42 erg/s (W) and L_X ~ 0.4 x 10^42 erg/s (E). The inferred X-ray luminosity is at least a factor of 3 higher than that expected from a pure starburst with the bolometric luminosity of Arp 220. For a typical AGN SED the bolometric luminosities are 5.2 x 10^43 erg/s (W) and 2 x 10^42 erg/s (E).