Redshift Velocity Research Articles

Observations of high velocity gas in the local interstellar medium

Red-shifted high velocity gas components (HVC) with velocities between 40 to 120 kms −1 have been detected in UV spectra towards several stars observed with IUE. The gas producing the components is detected across several degrees in the sky but it is patchy in nature. The physical properties of the material responsible for the HVC appear quite similar to those derived from direct observations of supernova remnants. Recent additional observations of the gas kinematics have been made through high resolution spectra of the NaD lines. Also, IRAS maps of infrared dust emission are presented for one region of sky of particular interest. In this report we review the observational material and discuss possibilities for the nature and origin of the HVC gas.

A COSMOLOGICAL CORRESPONDENCE PRINCIPLE

ABSTRACT A new explanation is offered for the increase in angular diameter of redshifted galaxies above that given by the inverse distance relationship. (A physical explanation is frequently given in terms of the curvature of space, but the increase due to this curvature factor is much less). The increase proportional to (1+z) and the quantity cz are global observables of an expanding universe which, in the limit of small z, correspond to the local observables of the relative change in angle due to the aberration of light and to the Doppler velocity, respectively. Neglect of the increase in angular diameter and of the increase in redshift velocity difference of binary galaxies leads to an overestimate of their masses by the factor (1+z)-to-the-4th.

A connection between galaxy probabilities in zwicky clusters counting distributions in particle physics and quantum optics

We have evaluated the probability distribution for finding n galaxies in a Zwicky cluster for six regions of the sky for a depth sample corresponding to 15 × 10 3 km/s < V s < 60 × 10 3 km/s red-shift velocity. Two regions differ from the other four by having a significantly greater high multiplicity tail and a lower peak value. In our view these tails correspond to ongoing gravitational coalescence of clusters, which is more effective in more heterogeneous regions. We obtain by subtraction a distribution to be identified with the original cluster distribution. The form of this distribution belongs to a general class characteristic of chaotic production mechanisms already identified in photoelectron counts from thermal sources and in hadronic charged particle multiplicity distributions. The possible nature of this universal mechanism is discussed.

Neutral hydrogen in binary and multiple galaxies

view Abstract Citations (37) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Neutral hydrogen in binary and multiple galaxies. Helou, G. ; Salpeter, E. E. ; Terzian, Y. Abstract H I observations of 28 galaxies, performed using the 305 m antenna at the 21 cm line, are reported for those galaxies belonging to pairs or small groups. The Arecibo beam is the primary H I distribution detector, and the size, flux and mass, redshift and rotation velocity, and spin orientation for each object are presented. Total indicative mass in individual galaxies and individual mass-to-light ratios, and nominal pair mass (for each pair, only statistically valid), are derived. It is noted that total mass-to-light ratios tend to be very similar within pairs. H I contour maps are included. Publication: The Astronomical Journal Pub Date: November 1982 DOI: 10.1086/113235 Bibcode: 1982AJ.....87.1443H Keywords: Galactic Structure; Hydrogen Clouds; Neutral Gases; Spiral Galaxies; Angular Velocity; Astronomical Maps; Centimeter Waves; Contours; Galactic Rotation; Mass To Light Ratios; Radiant Flux Density; Red Shift; Astronomy full text sources ADS | data products SIMBAD (29) NED (20)

The structure of the Hercules supercluster

Counts by Shane and Wirtanen detected a cloud of Galaxies - the Hercules Supercluster - centered at about α = 16h02m; δ = 17°00m. It is unclear whether there is a physical connection with another cloud located to the south for which no radial velocities are yet available and with the system A2197/A2199 located to the north. the latter is at slightly smaller redshift (velocities between 8000–11,000 km sec−1) than the Hercules cluster.

The Peculiar Extragalactic System NGC 6438

The peculiarly interacting extragalactic system NGC 6438 has been investigated, and it is shown that the irregular component and the S0 component have about the same redshift velocity of +2400 km/sec. Hence, the large velocity differences originally reported by Sersic (1968) are not confirmed.

HD 152667, A Spectroscopic Binary P Cygni Star

The spectroscopic binary P Cygni star, HD 152667 has been the subject of a radial velocity investigation. It is found to have a 7.84825 day period. Only one spectrum is visible but both primary and secondary eclipses have been observed at the Cape Observatory. The primary is a BoIae star. The material which causes the emission profiles is found to be associated with the primary component and to have a red-shifted radial velocity of approximately 300 km s –1 compared with the primary star. There is evidence for intrinsic radial velocity variations superimposed on the orbital motion of the star. It is possible that these intrinsic variations are a periodic phenomenon. The star is near to the cluster NGC 6231 in the sky and is possibly a member of this cluster.

A Search for Intergalactic Neutral Hydrogen: I. The Observations

A search was made of the radio-frequency spectrum of Cygnus A and Virgo A for absorption arising from intergalactic neutral hydrogen. A switched-frequency receiving technique which incorporated a large frequency scan was used in the investigation. The upper limit (95 per cent probability) to the optical depth of hydrogen at the red-shifted velocity of Cygnus A was placed at ≼ 0.0012. This is fifty times less than the effect originally claimed by Lilley & McClain. The optical depth of absorption due to intergalactic hydrogen is less than 0.0009 and a complementary experiment to measure emission from intergalactic neutral hydrogen showed that the emission temperature was less than 0.57°K. The observations of Virgo A revealed no intergalactic absorption features greater than an optical depth of 0.02.

Motions in Barred Spiral Galaxies. II the Rotation of NGC 7479.

view Abstract Citations (52) References (5) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Motions in Barred Spiral Galaxies. II the Rotation of NGC 7479. Burbidge, E. Margaret ; Burbidge, G. R. ; Prendergast, K. H. Abstract The barred spiral galaxy NGC 7479 is shown and described. Spectra were obtained with the B spectrograph at the prime focus of the 82-inch telescope, with the slit in various orientations. The velocity-curve obtained from two spectra taken along the bar is plotted; it is approximately linear over the length of the bar, but the velocity falls sharply outside the bar. Velocities were also measured in some knots in one of the spiral arms. The orientation of the galaxy in space was obtained by drawing an elliptical contour to contain the outermost visible parts and then by assuming this to be circular in the plane of the galaxy. An estimate of the mass of the bar has been made by assuming it to be a prolate spheroid of uniform density, rotating end over end at the observed angular velocity. The mass derived is 2.2 X 1010 M0. The mean red-shift velocity of NGC 7479 is 2421 km/sec (2637 km/sec when corrected for rotation of our Galaxy), giving a distance of 35.2 x 100 pc if a Hubble constant of 75 km/sec/mpc is used. The length of the bar in the plane of the galaxy is about 18.5 kpc. The sharp falloff in velocity in the arms outside the bar may be indicative of streaming motions. Publication: The Astrophysical Journal Pub Date: November 1960 DOI: 10.1086/146968 Bibcode: 1960ApJ...132..654B full text sources ADS | data products SIMBAD (1) NED (1) Related Materials (6) Part 1: 1960ApJ...132...30B Part 3: 1960ApJ...132..661B Part 4: 1962ApJ...136..119B Part 5: 1962ApJ...136..704B Part 6: 1964ApJ...140...85B Part 7: 1964ApJ...140...94R