This catalog summarizes 117 high-confidence > 0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on the Fermi satellite. Half are neutron stars discovered using LAT data, through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The 117 pulsars are evenly divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. We characterize the pulse profiles and energy spectra and derive luminosities when distance information exists. Spectral analysis of the off-peak phase intervals indicates probable pulsar wind nebula emission for four pulsars, and off-peak magnetospheric emission for several young and millisecond pulsars. We compare the gamma-ray properties with those in the radio, optical, and X-ray bands. We provide flux limits for pulsars with no observed gamma-ray emission, highlighting a small number of gamma-faint, radio-loud pulsars. The large, varied gamma-ray pulsar sample constrains emission models. Fermi's selection biases complement those of radio surveys, enhancing comparisons with predicted population distributions.

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The second fermi large area telescope catalog of gamma-ray pulsars

We investigate the birth and evolution of Galactic isolated radio pulsars. We begin by estimating their birth space velocity distribution from proper-motion measurements of Brisken and coworkers. We find no evidence for multimodality of the distribution and favor one in which the absolute one-dimensional velocity components are exponentially distributed and with a three-dimensional mean velocity of 380 km s-1. We then proceed with a Monte Carlo-based population synthesis, modeling the birth properties of the pulsars, their time evolution, and their detection in the Parkes and Swinburne Multibeam surveys. We present a population model that appears generally consistent with the observations. Our results suggest that pulsars are born in the spiral arms, with a galactocentric radial distribution that is well described by the functional form proposed by Yusifov & Kucuk, in which the pulsar surface density peaks at radius ~3 kpc. The birth spin period distribution extends to several hundred milliseconds, with no evidence of multimodality. Models that assume the radio luminosities of pulsars to be independent of the spin periods and period derivatives are inadequate, as they lead to the detection of too many old simulated pulsars in our simulations. Dithered radio luminosities proportional to the square root of the spin-down luminosity accommodate the observations well and provide a natural mechanism for the pulsars to dim uniformly as they approach the death line, avoiding an observed pileup on the latter. There is no evidence for significant torque decay (due to magnetic field decay or otherwise) over the lifetime of the pulsars as radio sources (~100 Myr). Finally, we estimate the pulsar birthrate and total number of pulsars in the Galaxy.

https://iopscience.iop.org/article/10.1086/501516/pdf

Birth and Evolution of Isolated Radio Pulsars

We have compiled a catalog of absolute proper motions of globular clusters from various sources. The sample consists of 38 clusters, from which most of the southern ones (15 clusters) were measured in our previous papers in this series. We have integrated orbits assuming two different Galactic potential models adopted from the literature and have calculated orbital parameters. The uncertainties associated with the orbital parameters were derived in a Monte Carlo approach, and we conclude that, overall, at the present level of measurement errors, orbital differences due to Galactic potential models are not significant. Three metal-poor clusters are found to have orbits similar to prototypical metal-rich disk clusters. These clusters are NGC 6254 (M10), NGC 6626 (M28), and NGC 6752. We interpret this as a potentially significant constraint on the formation of the disk. It is thus possible that part of the inner metal-poor halo is the low-metallicity tail of the thick disk. In this case, the ages of these clusters indicate that the formation of the disk partially overlapped with that of the halo. The clusters classified as young halo or red horizontal-branch by Zinn show a radially anisotropic velocity distribution, their orbits are of high total energy, with apocentric radii larger than 10 kpc and highly eccentric. In this sense they may represent an accreted component of our Galaxy. We also discuss ω Cen's orbit characteristics in the view of an accreted origin. We investigate the effect of the orbital motion on the internal dynamics of clusters. Adopting the formalism from Gnedin & Ostriker and their destruction rates due to two-body relaxation, we find that, in most cases, this internal process is more important than the destruction processes due to disk and bulge shocking. Hubble Space Telescope (HST) observations argue that NGC 6397's luminosity function is depleted at the faint end, and this is blamed on its high total destruction rate. We propose a list of clusters with similar destruction rates that may also have depleted luminosity functions. We also note the bias toward deriving higher destruction rates in studies that statistically assign tangential velocities based on a kinematic model of the globular cluster system, in contrast to the rates derived from the measured tangential velocities. Clusters prone to such biases are those that have circular orbits (kinematically thick-disk clusters) and some of those with orbits of high total energy.

https://iopscience.iop.org/article/10.1086/300807/pdf

Space Velocities of Globular Clusters. III. Cluster Orbits and Halo Substructure

We investigated the reported distances of Galactic black hole (BH) and neutron star low-mass X-ray binaries (LMXBs). Comparing the distances derived for the neutron stars Cyg X-2 and XTE J2123-058 using the observed Eddington limited photospheric radius expansion bursts with the distances derived using the observed radius and effective temperature of the companion star, we find that the latter are smaller by approximately a factor of 1.5-2. The latter method is often employed to determine the distance to BH LMXBs. A possible explanation for this discrepancy is that the stellar absorption lines in fast rotating companion stars are different from those in the slowly rotating template stars as was found before for early-type stars. This could lead to a systematic mis-classification of the spectral type of the companion star, which in turn would yield a systematic error in the distance. Further, we derive a distance of 4.0 +2.0 -1.2 ) kpc for V404 Cyg, using parameters available in the literature. The interstellar extinction seems to have been overestimated for XTE J1550-564 and possibly for two other BH sources (H 1705-25 and GS 2000+25) as well. As a result of this, the distance to XTE J1550-564 may have been underestimated by as much as a factor three. We find that, using the new distances for XTE J1550-564 and V404 Cyg, the maximum outburst luminosity for at least five, but perhaps even seven, of the 15 BH soft X-ray transients exceed the Eddington luminosity for a 10-M ○. BH - showing that these systems would be classified as ultra-luminous X-ray sources had we observed them in other Galaxies. This renders support for the idea that many ultra-luminous X-ray sources are stellar-mass rather than intermediate-mass BHs. We find that the rms-value of the distance to the Galactic plane for BHs is consistent with that of neutron star LMXBs. This suggests that BHs could also receive a kick-velocity during their formation, although this has to be investigated in more detail. We find that the Galactic neutron star and BH l- and b-distributions are consistent with being the same. The neutron star and BH distribution is asymmetric in l with an excess of systems between -30° < l < 0° over systems with 0° < l < 30°.

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The distances to Galactic low-mass X-ray binaries: consequences for black hole luminosities and kicks

We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r 20°). We find that in the region defined by 1 kpc <Z< 5 kpc and 3 kpc <R< 13 kpc, the rotational velocity for disk stars smoothly decreases, and all three components of the velocity dispersion increase, with distance from the Galactic plane. In contrast, the velocity ellipsoid for halo stars is aligned with a spherical coordinate system and appears to be spatially invariant within the probed volume. The velocity distribution of nearby (Z < 1 kpc) K/M stars is complex, and cannot be described by a standard Schwarzschild ellipsoid. For stars in a distance-limited subsample of stars (<100 pc), we detect a multi-modal velocity distribution consistent with that seen by HIPPARCOS. This strong non-Gaussianity significantly affects the measurements of the velocity-ellipsoid tilt and vertex deviation when using the Schwarzschild approximation. We develop and test a simple descriptive model for the overall kinematic behavior that captures these features over most of the probed volume, and can be used to search for substructure in kinematic and metallicity space. We use this model to predict further improvements in kinematic mapping of the Galaxy expected from Gaia and the Large Synoptic Survey Telescope.

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The Milky Way Tomography with SDSS: III. Stellar Kinematics

Our galaxy has a substantial nucleus that exhibits itself as a strong rise in the rotation curve inside of 2 kpc, peaking around 500 pc. Stars with very eccentric orbits that pass through the nuclear region generally cannot be confined to a flattened disk distribution; instead, they spend most of their time in the halo. In a local sample of high-velocity-dispersion disk stars, there should be an apparent deficiency of stars with very low angular momenta, because they are scattered to much higher scale heights. The deficiency or gap will be centered on the circular velocity as reflected in the motion of the LSR. Using a new galactic model, we calibrate the predicted depression in the distribution of tangential velocities, finding a half-width of 40 km s -1 with a depth greater than 80%. We present evidence that the expected deficiency of low-angular-momentum stars does exist in the local stars. The strength of the conclusion is limited by the small size of the current sample of appropriate intermediate-population stars: those that are both in a strongly flattened distribution and possess significant numbers of members at low angular momentum. The available data favor a scale and model-free circular velocity at the Sun in the range 225-245 km s with a most probable value of 235 km s. Larger samples that are forthcoming will allow this simple method to be applied with much greater confidence.

K. A. Innanen

Papers

Galactic Chaos and the Circular Velocity at the Sun