Searching for bulk motions in the ICM of massive, merging clusters with Chandra CCD data

We search for bulk motions in the intracluster medium (ICM) of massive clusters showing evidence of an ongoing or recent major merger with spatially resolved spectroscopy in {\sl Chandra} CCD data. We identify a sample of 6 merging clusters with $>$150 ks {\sl Chandra} exposure in the redshift range $0.1 < z < 0.3$. By performing X-ray spectral analysis of projected ICM regions selected according to their surface brightness, we obtain the projected redshift maps for all of these clusters. After performing a robust analysis of the statistical and systematic uncertainties in the measured X-ray redshift $z_{\rm X}$, we check whether or not the global $z_{\rm X}$ distribution differs from that expected when the ICM is at rest. We find evidence of significant bulk motions at more than 3$\sigma$ in A2142 and A115, and less than 2$\sigma$ in A2034 and A520. Focusing on single regions, we identify significant localized velocity differences in all of the merging clusters. We also perform the same analysis on two relaxed clusters with no signatures of recent mergers, finding no signs of bulk motions, as expected. Our results indicate that deep {\sl Chandra} CCD data enable us to identify the presence of bulk motions at the level of $v_{\rm BM} >$ 1000\ ${\rm km\ s^{-1}}$ in the ICM of massive merging clusters at $0.1<z<0.3$. Although the CCD spectral resolution is not sufficient for a detailed analysis of the ICM dynamics, {\sl Chandra} CCD data constitute a key diagnostic tool complementing X-ray bolometers on board future X-ray missions

Entanglement spectrum: Identification of the transition from vortex-liquid to vortex-lattice state in a weakly interacting rotating Bose-Einstein condensate

We use entanglement to investigate the transition from vortex liquid phase to vortex lattice phase in weakly interacting rotating Bose-Einstein condensate (BEC). Ground state entanglement spectrum is analyzed to distinguish these two different phases. For the torus geometry, the low-lying part of ground state entanglement spectrum, as well as the behavior of its lowest level change clearly when the transition occurs. For the sphere geometry, the disappearance of entanglement gap in the conformal limit (CL) can indicate this transition. We also show that the decrease of entanglement between particles can be regarded as a signal of the transition.Comment: published versio

Charged fusions for enhanced protein purification and immobilization by ion-exchange

This work was undertaken to investigate the enhanced binding of genetically engineered [beta]-galactosidase fusions in ion-exchange. The fusions used had a series of polyaspartate tails of the form: Gly-Asp-Pro-Met-Ala-(Asp)[subscript] n-Tyr fused to the carboxyl termini of the wild type [beta]-galactosidase (BGWT). The resulting fusions carried additional 1, 5, 11, and 16 negative charges and are designated as BGCD1, BGCD5, BGCD11, and BGCD16, respectively;The use of charged fusions for selective protein recovery was studied using hollow fiber ion-exchange membranes. The added tails allowed selective binding and release of [beta]-galactosidase in active form from Escherichia coli cell extract. The purification factors increased with fusion length. For BGCD11, more than six fold enrichment in [beta]-galactosidase was obtained. The specific activity was comparable to that of commercial wild type and affinity-purified [beta]-galactosidase;The potential end use advantages of the fusions for immobilization was studied using flat sheet ion-exchange membranes. The added tails did not interfere with the kinetic behavior for lactose hydrolysis. The enhanced binding of BGCD11 on the membrane enabled the enzyme to hydrolyze acid whey permeate at 0.3 M ionic strength without leakage. An intregated separation and immobilization scheme was illustrated by the development of an immobilized enzyme reactor directly from cell extract;The protein retention behavior was investigated using high performance liquid chromatography with perfusion packings. The added tails promoted retention which increased with the tail length (charge) and were best utilized closer to the isoelectric point. The two parameters, Z and I, obtained from the stoichiometric displacement model were used to characterize the protein interaction with the ion-exchange surface. At pH 5.7, the Z number increased with tail length (charge) and was 11.5, 8.5, 6.9 and 5.3 for BGCD11, BGCD5, BGCD1 and BGWT, respectively. At these conditions, the fusions had very similar I values which were five times smaller than those of BGWT. However, the increase in Z numbers outweighed the decrease in I values and an overall enhanced retention was reported. When BGWT was brought to the same net charge (by increasing the mobile phase pH) as each of the fusions, the Z number was similar to that of the corresponding fusion. However, the I values decreased with increasing pH (net charge) and were lower than that of the corresponding fusion. Consequently, despite the similar Z numbers, the fusions had a higher retention

Electromagnetic radiation of baryons containing two heavy quarks

The two heavy quarks in a baryon which contains two heavy quarks and a light one, can constitute a scalar or axial vector diquark. We study electromagnetic radiations of such baryons, (i) \Xi_{(bc)_1} -> \Xi_{(bc)_0}+\gamma, (ii) \Xi_{(bc)_1}^* -> \Xi_{(bc)_0}+\gamma, (iii) \Xi_{(bc)_0}^{**}(1/2, l=1) -> \Xi_{(bc)_0}+\gamma, (iv) \Xi_{(bc)_0}^{**}(3/2, l=1) -> \Xi_{(bc)_0}+\gamma and (v) \Xi_{(bc)_0}^{**}(3/2, l=2) -> \Xi_{(bc)_0}+\gamma, where \Xi_{(bc)_{0(1)}}, \Xi^*_{(bc)_1} are S-wave bound states of a heavy scalar or axial vector diquark and a light quark, and \Xi_{(bc)_0}^{**}(l is bigger than 1) are P- or D-wave bound states of a heavy scalar diquark and a light quark. Analysis indicates that these processes can be attributed into two categories and the physical mechanisms which are responsible for them are completely distinct. Measurements can provide a good judgment for the diquark structure and better understanding of the physical picture.Comment: 15 pages, Late

Chebyshev's maximum principle in several variables

AbstractIn this short note, we discuss the Chebyshev's maximum principle in several variables. We show some analogous maximum formulae for the common zeros in some special cases. It can be regarded as the extension of the univariate case

Precision cosmology from future lensed gravitational wave and electromagnetic signals

The standard siren approach of gravitational wave cosmology appeals to the direct luminosity distance estimation through the waveform signals from inspiralling double compact binaries, especially those with electromagnetic counterparts providing redshifts. It is limited by the calibration uncertainties in strain amplitude and relies on the fine details of the waveform. The Einstein Telescope is expected to produce $10^4-10^5$ gravitational wave detections per year, $50-100$ of which will be lensed. Here we report a waveform-independent strategy to achieve precise cosmography by combining the accurately measured time delays from strongly lensed gravitational wave signals with the images and redshifts observed in the electromagnetic domain. We demonstrate that just 10 such systems can provide a Hubble constant uncertainty of $0.68\%$ for a flat Lambda Cold Dark Matter universe in the era of third generation ground-based detectors

Poly[(μ2-benzene-1,3-dicarboxyl­ato-κ2 O 1:O 3){μ2-1,2-bis­[(1H-imidazol-1-yl)meth­yl]benzene-κ2 N 3:N 3′}zinc]

In the two-dimensional title coordination polymer, [Zn(C8H4O4)(C14H14N4)]n, the ZnII atom adopts a distorted tetra­hedral geometry, being ligated by two O atoms from two different benzene-1,3-dicarboxyl­ate dianions and two N atoms from two symmetry-related 1,2-bis­(imidazol-1-ylmeth­yl)benzene mol­ecules. The dihedral angles between the imidazole rings and the benzene ring in the neutral ligand are 76.31 (13) and 85.33 (15)°. The ZnII atoms are bridged by dicarboxyl­ate ligands, forming chains parallel to the a axis, which are further linked by 1,2-bis­(imidazol-1-ylmeth­yl)benzene mol­ecules, generating a two-dimensional layer structure parallel to the ac plane. The crystal structure is enforced by intra­layer and inter­layer C—H⋯O hydrogen bonds