cD Envelope Research Articles

The structure of brightest cluster members. III - cD envelopes

Single-band photographic and CCD surface photometry is used to determine luminosity and structural properties of the extended, faint envelopes around 27 cD galaxies. The distribution of envelope light follows a similar slope as other cluster luminous material. Several correlations between envelope luminosity and cluster properties substantiate arguments for the dynamical formation of envelopes. A correlation between underlying galaxy luminosity and envelope luminosity implies a parallel but separate process between the growth of the first-ranked elliptical by mergers and cD envelope formation. Strong color gradients, in particular the blue disk colors as predicted by other studies, were not found upon examination of multicolor profiles for three cD envelopes. 50 references.

Domain specificity in metal binding to metallothionein. A circular dichroism and magnetic circular dichroism study of cadmium and zinc binding at temperature extremes.

Rabbit liver Zn metallothionein-(MT) will bind cadmium readily between -26 degrees C and 70 degrees C. The binding reaction was monitored by recording the circular dichroism and magnetic circular dichroism spectra, in the region of the RS(-)----Cd2+ charge transfer transition at 250 nm, at intervals as aliquots of cadmium were added. For all temperatures, these data can be analyzed in terms of a distributed mechanism for cadmium binding when Zn-MT is used, and a domain-specific mechanism when apo-MT is used. The CD spectrum measured at -26 degrees C for Cd,Zn-MT, which was made by adding excess cadmium directly to Zn7-MT at -26 degrees C, is not the same as the CD spectrum of Cd-MT prepared at room temperature from the same Zn7-MT. Measurements of the stoichiometry of the cadmium and zinc bound to MT in the presence of excess cadmium at different temperatures indicates that below 5 degrees C at least one zinc atom remains bound to the protein. The mixed metal metallothionein, Cd/Zn-MT, that always forms below 5 degrees C, is characterized by a single maximum near 250 nm in the CD spectrum, rather than the derivative-shaped CD envelope that is diagnostic of the (Cd4-S11)alpha cluster, which indicates that the zinc occupies a site in the alpha domain. Rearrangement of the bound metals to the domain-specific distribution takes place if Cd,Zn-MT, prepared at subzero temperatures, is warmed above 30 degrees C.

The dynamics and structure of the cD galaxy in Abell 2029

view Abstract Citations (191) References (39) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The dynamics and structure of the cD galaxy in Abell 2029. Dressler, A. Abstract Spectra of the envelope of the cD galaxy in the rich cluster of galaxies Abell 2029 out to over 100 kpc are analyzed by using a Fourier cross-correlation technique. It is found that the measured velocity dispersion apparently increases with radius, implying that the M/L ratio of the envelope is increasing rapidly. All that is presently known about the cluster and the cD galaxy is accounted for by a three-component King (1966) model consisting of a 'normal elliptical' galaxy, a high-M/L cluster-filling and cluster-binding superstructure, and a component of intermediate M/L and velocity dispersion that supplies the light of the 'extended halo'. The high-M/L component is tentatively identified with stripped dark halos of cluster galaxies, and the intermediate-M/L material is attributed to the dynamical friction process that disrupts massive luminous galaxies as they encounter the cD envelope. Publication: The Astrophysical Journal Pub Date: August 1979 DOI: 10.1086/157229 Bibcode: 1979ApJ...231..659D Keywords: Astrodynamics; Galactic Clusters; Galactic Structure; Astronomical Photography; Cross Correlation; Data Processing; Density Distribution; Graphs (Charts); Stellar Luminosity; Stellar Spectra; Astrophysics; Clusters of Galaxies:Giant Galaxies; Galaxies:Dynamics; Galaxies:Spectra; Galaxies:Structure full text sources ADS | data products NED (2) SIMBAD (1)