We present redshifts for a sample of 4391 galaxies with magnitude mB(0) ≤ 15.5 covering 20h ≤ α ≤ 4h in right ascension and -25 ≤ δ ≤ 90° in declination. This sample is complete for all galaxies in the merge of the Zwicky et al. and Nilson catalogs in the south Galactic cap. Redshifts for 2964 of these were measured as part of the second CfA Redshift Survey. The data reveal large voids in the foreground and background of the Perseus-Pisces Supercluster. The largest of these voids lies at a mean velocity ~8000 km s-1, has diameter ~5000 km s-1, and is enclosed by a complex of dense structures. The large structure known as the Perseus-Pisces Supercluster forms the near side of this complex. On the far side of this large void, at a mean velocity ~12,000 km s-1, there is another coherent dense wall. The structures in this survey support the view that galaxies generally lie on surfaces surrounding or nearly surrounding low-density regions or voids.

https://iopscience.iop.org/article/10.1086/313194/pdf

The CfA Redshift Survey: Data for the South Galactic Cap*

We report the discovery of an L-type companion to the young M3.5V star 2MASS J01225093-2439505 at a projected separation of 1.''45 (52?AU) as part of our adaptive optics imaging search for extrasolar giant planets around young low-mass stars. 2MASS 0122-2439 B has very red near-infrared colors similar to the HR?8799 planets and the reddest known young/dusty L dwarfs in the field. Moderate-resolution (R 3800) 1.5-2.4 ?m spectroscopy reveals a near-infrared spectral type of L4-L6 and an angular H-band shape, confirming its cool temperature and young age. The kinematics of 2MASS 0122-2439 AB are marginally consistent with members of the ~120?Myr AB Dor young moving group based on the photometric distance to the primary (36 ? 4?pc) and our radial velocity measurement of 2MASS 0122-2439 A from Keck/HIRES. We adopt the AB Dor group age for the system, but the high energy emission, lack of Li?I ?6707 absorption, and spectral shape of 2MASS?0122-2439?B suggest a range of ~10-120?Myr is possible. The age and luminosity of 2MASS 0122-2439 B fall in a strip where hot-start evolutionary model mass tracks overlap as a result of deuterium burning. Several known substellar companions also fall in this region (2MASS J0103-5515 ABb, AB Pic b, ? And b, G196-3 B, SDSS 2249+0044 B, LP?261-75?B, HD?203030?B, and HN Peg B), but their dual-valued mass predictions have largely been unrecognized. The implied mass of 2MASS 0122-2439 B is 12-13 M Jup or 22-27 M Jup if it is an AB Dor member, or possibly as low as 11 M Jup if the wider age range is adopted. Evolutionary models predict an effective temperature for 2MASS 0122-2439?B that corresponds to spectral types near the L/T transition (1300-1500?K) for field objects. However, we find a mid-L near-infrared spectral type, indicating that 2MASS 0122-2439 B represents another case of photospheric dust being retained to cooler temperatures at low surface gravities, as seen in the spectra of young (8-30?Myr) planetary companions. Altogether, the low mass, low temperature, and red colors of 2MASS?0122-2439?B make it a bridge between warm planets like ? Pic b and cool, very dusty ones like HR?8799?bcde.

https://iopscience.iop.org/article/10.1088/0004-637X/774/1/55/pdf

Planets around low-mass stars. iii. a young dusty l dwarf companion at the deuterium-burning limit ,

We present an analysis of X-ray, ultraviolet and optical/near-IR photometric data of the transitional millisecond pulsar binary XSS J12270−4859, obtained at different epochs after the transition to a rotation-powered radio pulsar state. The observations, while confirming the large-amplitude orbital modulation found in previous studies after the state change, also reveal an energy dependence of the amplitudes as well as variations on time-scale of months. The amplitude variations are anticorrelated in the X-ray and the UV/optical bands. The average X-ray spectrum is described by a power law with Γ index of 1.07(8) without requiring an additional thermal component. The power-law index Γ varies from ∼1.2 to ∼1.0 between superior and inferior conjunction of the neutron star. We interpret the observed X-ray behaviour in terms of synchrotron radiation emitted in an extended intrabinary shock, located between the pulsar and the donor star, which is eclipsed due to the companion orbital motion. The G5-type donor dominates the UV/optical and near-IR emission and is similarly found to be heated up to ∼6500 K as in the disc state. The analysis of optical light curves gives a binary inclination 46° ≲ i ≲ 65° and a mass ratio 0.11 ≲ q ≲ 0.26. The donor mass is found to be 0.15 ≲ M2 ≲ 0.36 M⊙ for a neutron star mass of 1.4 M⊙. The variations in the amplitude of the orbital modulation are interpreted in terms of small changes in the mass-flow rate from the donor star. The spectral energy distribution from radio to gamma-rays is composed by multiple contributions that are different from those observed during the accretion-powered state.

/pdf/multiwavelength-observations-of-the-transitional-millisecond-125jesxx66.pdf

Multiwavelength observations of the transitional millisecond pulsar binary XSS J12270-4859

We present the high angular resolution technique of colour-differential interferometry for direct detection of extrasolar giant planets (EGPs). The measurement of differential phase with long-baseline ground-based interferometers in the near-infrared could allow the observation of several hot giant extrasolar planets in tight orbit around the nearby stars, and thus yield their low- or mid-resolution spectroscopy, complete orbital data set and mass. Estimates of potentially achievable signal-to-noise ratios are presented for a number of planets already discovered by indirect methods. The limits from the instrumental and atmospheric instability are discussed, and a subsequent observational strategy is proposed.

/pdf/colour-differential-interferometry-for-the-observation-of-3nv7yact2o.pdf

Colour-differential interferometry for the observation of extrasolar planets

The modes of operation of photoconductive and photoemissive array detectors are described, and their performance characteristics compared and contrasted, with emphasis on their suitability for use as detectors for optical spectroscopy. The prospects for future developments of the array detectors are discussed.

Optical detectors for spectroscopy

Instrumentation for astronomy with large optical telescopes

Instrumentation for astronomy with large optical telescopes : proceedings of IAU colloquium no. 67, held at Zelenchukskaya, U.S.S.R., 8-10 September, 1981

Colin M. Humphries

Papers

Instrumentation for astronomy with large optical telescopes

Instrumentation for astronomy with large optical telescopes : proceedings of IAU colloquium no. 67, held at Zelenchukskaya, U.S.S.R., 8-10 September, 1981