Red Magnitude Research Articles

A Redshift Survey of Very Faint (B≤22.5) Field Galaxies, Radio Sources, and Quasars

As part of a three year program to study the evolution of galaxies, quasars, and radio sources (in collaborations with R. Kron and R. Windhorst), we will use over 30 nights on the KPNO 4-m CCD Cryogenic Camera System, in the multi-aperture mode, to measure the redshifts of several hundred very faint objects. These will be selected from four fields (SA68 00h+15; Lynx 08h+45; SA57 13h+30; Herc 17h+50); for each we possess 4-m plates in four bandpasses (limits: U≃23, B≃24, V≃23, I≃21) as well as Westerbork interferometer maps to 1 mJy at 21cm (a 50cm survey is in progress). Galaxies are selected randomly by their apparent red magnitudes as measured with a PDS; quasar candidates to B≈22.5 by stellar objects which lie apart from Galactic stars in the multi-color diagram; and radio sources by their positional coincidence with optical images (∼50% of the 300 radio sources are identified). To date, 10 nights have produced spectra of ∼250 field galaxies, ∼20 radio sources, and ∼40 quasar candidates.

The Metallic Hydride Dwarfs

The properties of the M dwarfs have been investigated by spectroscopic and photometric observations of over 150 red, high proper motion stars. Most of these stars have red magnitudes fainter than 12 magnitude.

Characteristics of Nebulosity Associated with Parkes Quasars

A sample of 13 out of 15 low redshift (0.1 ≤ z ≤ 0.6) radio-loud quasars have been resolved on large-scale (19 arcsec mm−1), sky-limited (µR ∼ 26.5 mag sec−2) Kodak IIIa-F photographs obtained with the ESO 3.6-m telescope. The QSO images were analyzed by digitally subtracting the plate background and the point-spread function defined by images of nearby (≤ 1 arcmin) field stars having magnitudes comparable to the quasars (Δm ≲ 0.3 mag). The resolved nebulosities underlying the QSO images have isophotal diameters in the range θ ∼ 7 to 40 arcsec, with surface brightnesses µR ∼ 22–26 mag sec−2, and integrated apparent red magnitudes ∼ 16–21.

The resolution of old red giant stars in the Sculptor group of galaxies

view Abstract Citations (46) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The resolution of old red giant stars in the Sculptor group of galaxies. Graham, J. A. Abstract Photographs are reproduced showing the resolution of the old red giant stars in the galaxies NGC 55 and NGC 300 which belong to the nearby Sculptor group of galaxies. The red magnitude of these stars is estimated to be 22.0 + or - 0.3 mag which corresponds to a visual magnitude of 23.0 mag. A comparison with NGC 205, a companion galaxy of M31, suggests an upper limit of 1.9 Mpc (modulus 26.4 mag) for the distances to NGC 55 and NGC 300. A similar degree of resolution is not seen in NGC 253 which is probably a more distant object. It is concluded that, like the members of the Local Group, the Sculptor galaxies are distributed over a large volume of space with NGC 55 and NGC 300 on the near side of the loose aggregate. Publication: The Astrophysical Journal Pub Date: January 1982 DOI: 10.1086/159575 Bibcode: 1982ApJ...252..474G Keywords: Astronomical Photography; Galactic Clusters; Image Resolution; Late Stars; Red Giant Stars; Stellar Magnitude; Galactic Evolution; Galactic Structure; Spatial Distribution; Stellar Evolution; Astrophysics full text sources ADS | data products SIMBAD (4) NED (3)

UV spectra of the twin QSOs 0957+561 A, B

Observations of the twin QSOs 0957+561 A and B by Walsh et al.1 gave the same redshifts in both the emission line (ze=1.41) and absorption line (za=1.39) systems and also showed similar spectral characteristics in the strengths of the emission lines, absorption lines and continua. This led to the proposal that they were one object, a double image of which was being formed by an intervening massive galaxy acting as a gravitational lens. More extended observations in the 6,000–6,900 A range2 and in the 4,000–7,000 A region3 confirm the similarity of the two spectra and show very close agreement (14 kms−1 r.m.s.) between the velocities of the absorption line systems, thus strengthening the lens hypothesis. Other data on the structure of the associated radio sources4–6 are also consistent with the above proposition. An intervening galaxy has been looked for7 which may act as a gravitational lens: very deep red images were taken of the field using a CCD camera on the 200-inch Palomar telescope and supplemented by multichannel spectrophotometric scans of the double system. An elliptical galaxy of red magnitude 18.5 was detected which is nearly superimposed on the south (B) component of the twin QSO and which is the brightest member of a rich cluster of galaxies. The spectrophotometric data of the system show a contribution from this intervening galaxy and from the location of the characteristic Ca II 3,950 A break, a redshift of 0.39 is estimated. Young et al.8 conclude that Q0957+561 A, B could be two images of the same object produced by this galaxy but that the lens properties are somewhat complex due to ‘aberrations’ induced by the rest of the cluster. We present here the first UV observations of Q0957+561 A, B and discuss them in terms of the lens hypothesis.

A Catalogue of Very Faint Clusters of Galaxies in the Region of the South Galactic Pole

In a search for very distant clusters of galaxies on a redsensitive (6° × 6°) Schmidt plate taken at Siding Spring in the region of the south galactic pole, we found some 49 very faint and compact clusters. We tried to reduce the number of chance configurations, by limiting our survey to (a) very compact and isolated groups of galaxylike images outside crowded regions; (b) some degree of concentration could be observed towards the brightest galaxy; (c) the size of the central object exceeded by several times the seeing disk diameter; (d) a minimum of 15 galaxies could be counted within a circle of ~ 30 arcsec in diameter. The red magnitudes of the brightest galaxies in each clusters are estimated to be fainter than 19.0 magnitudes. From the Hubble diagram for red magnitudes we estimate the redshifts to be about z ≥ 0.5. The integrated red magnitude of the first ranked galaxies in the faintest clusters are about 21.5. Taking into account seeing effects, a more realistic formula for the surface brightness at the centers of galaxies (rather than the [1 + z]−4) is derived. It is shown that, assuming no evolution, the limit of our survey corresponding to the faintest clusters is about z ≥ 1.0. A list of clusters coordinates, magnitudes of the first ranked galaxies and finding charts can be obtained from the author.

Spectroscopic observation of six new galaxies with ultraviolet continuum

The results are given of spectroscopic observations of galaxies with ultraviolet continuum discovered with the 40'' Schmidt telescope of the Byurakan Observatory with a 1.5/sup 0/ objective prism. All galaxies exhibit emission lines in their spectra. The spectra are described and the red shifts and absolute magnitudes of the galaxies are determined.

OPTICAL IDENTIFICATION OF NVA SCUTI 1975

ABSTRACT We have identffied Nova Scuti 1975 with a faint star on the Palomar Sky Survey. Estimates of blue and red magnitudes are given for both the nova and suggested prenova. Key words: novae - photometry - prenovae identification

Variable Stars In NGC 4590

AbstractThe globular cluster NGC 4590 has been observed at Haute Provence Observatory (photographic photometry, 80-cm reflector, F/6) and at the European Southern Observatory (image-tube, 152-cm reflector, F/15). – A sequence of red magnitudes, mr (λett ≅ 6400 Å) has been established around the cluster. It comprises 28 stars with magnitudes between 11.66 and 16.50.– Five new variable stars were discovered in a one square degree field, centered on the cluster.– Four other variable stars (No. 39, 40, 41, and 42) were discovered in the cluster.

A color-magnitude diagram for the Small Magellanic Cloud

view Abstract Citations (5) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A color-magnitude diagram for the Small Magellanic Cloud Schilt, J. ; Epstein, I. ; Hill, S. J. Abstract . Blue and red magnitudes for 1619 non-variable stars in the densest part of the Small Magellanic Cloud have been determined by the neutral half-screen method from plates taken with the 26-inch Yale-Columbia refractor and supplemented by means of photoelectric standards in the blue and yellow. The color-magnitude diagram corresponding to these measures has been constructed and is discussed in a preliminary manner. Publication: The Astronomical Journal Pub Date: October 1955 DOI: 10.1086/107234 Bibcode: 1955AJ.....60..341S full text sources ADS | data products NED (1)

Red Magnitudes of the North Polar Sequence Stars.

Red Magnitudes of the North Polar Sequence Stars.

Red magnitudes of 3555 faint A. G. stars in declination + 10' to + 15'

Red magnitudes of 3555 faint A. G. stars in declination + 10' to + 15'

Magnitudes and Colors in the Globular Cluster Messier 12 and Selected Area 108.

view Abstract Citations (3) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Magnitudes and Colors in the Globular Cluster Messier 12 and Selected Area 108. Nassau, J. J. ; Hynek, J. A. Abstract The present report deals with the determination of red magnitudes of stars in Selected Area 108 and with blue and red magnitudes in Messier 12, which is three degrees from the Selected Area. The red magnitudes of the bright stars of the former were determined by direct comparison with the North Polar Sequence; those of the faint stars, by means of a 72-inch wire objective grating attached to the 69-inch Perkins reflector. The red magnitudes of stars in Harvard Standard Region C9 were used to check the determinations for the brighter stars, and the relation between color indices and red indices was utilized to check the grating magnitudes. A sequence of stars with limiting red magnitude 15.21 and with an average probable error of ± O~O5 is given. From this sequence the red magnitudes of all stars brighter than 15~'18 in SA 108 have been determined. The adopted photographic modulus of M 12 is 13'~'9O, a value determined from the published modulus by correcting for interstellar absorption by means of the observed color excess of the cluster. This modu- lus gives 6.0 kpc for the distance of the cluster. The corresponding red modulus was found to be 14m70. Both red-and blue-magnitude sequences are given for the cluster. The red indices of all stars brighter than 13.46 red magnitude within 2~3 of the center of the cluster have been determined, and likewise the red indices of all stars brighter than 15.18 red magnitude within zones of 2 ~3 and 1O~4 are given. The frequency distribution of the red indices does not change with the distance from the center of the cluster. The essential features of the color-magnitude diagram of the stars in the cluster are: (a) the total absence of early-type supergiants; (b) the presence of very few stars in the region ordinarily occupied by cluster-type variables; (c) an abundance of red supergiants, together with a total absence of red giants; and (d) the presence of essentially two groups of stars, one group of early spectral class with constant absolute magnitude, and the other of late spectral class with absolute luminosity increasing with the red index (the two groups meet in the diagram at Mr ,= 0.0 and C~ = 0.75) Publication: The Astrophysical Journal Pub Date: July 1942 DOI: 10.1086/144431 Bibcode: 1942ApJ....96...37N full text sources ADS | data products SIMBAD (2)

Heterochromatic Studies of the Companions of Sirius, of O Ceti, and of o_{2} Eridani

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Heterochromatic Studies of the Companions of Sirius, of O Ceti, and of o_{2} Eridani Hetzler, Charles Abstract A simple device is described whereby the components of Sirius were separated at the photographic focus of the Thaw refractor. Methods of separation in the red and ultra- violet are sketched. Magnitudes for a number of Sirius field stars are derived in terms of the B9 field star, BD - 17°161 i, of magnitude 6.76. The resulting photograpFdc and red magnitudes of Sirius B, of probable error less than o~'i, are 7~95 and 8~~44, respec- tively, as compared with Wendell's visual value of 8~4, confirmed by Kuiper at Leiden and at the Lick Observatory, and with Vyssotsky's pI~oto-visua1 value of 7~I. TI~e corresponding magnitude of Sirius A is - i ~ without appreciable color index. Photo- graphic positions of components A and B of Sirius relative to field stars are given at intervals since 1932; resulting values of p and 0 are compared with calculated posi- tions and with recent visual observations. No sign of a third component is visible. Photographic and ultra-violet observations of o Ceti B are described. The photo- graphic magnitude in terms of that assumed for the distant companion to o Ceti is i 1.2. Several measurements of p and 0 are tabulated. As a comparison, the red and ultra-violet indices of 02 Eridani B are found to agree with those of Sirius B Publication: The Astrophysical Journal Pub Date: July 1935 DOI: 10.1086/143657 Bibcode: 1935ApJ....82...75H full text sources ADS |