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We use the WISE-2MASS infrared galaxy catalog matched with Pan-STARRS1 (PS1) galaxies to search for a supervoid in the direction of the Cosmic Microwave Background Cold Spot. Our imaging catalog has median redshift $z\simeq 0.14$, and we obtain photometric redshifts from PS1 optical colours to create a tomographic map of the galaxy distribution. The radial profile centred on the Cold Spot shows a large low density region, extending over 10's of degrees. Motivated by previous Cosmic Microwave Background results, we test for underdensities within two angular radii, $5^\circ$, and $15^\circ$. The counts in photometric redshift bins show significantly low densities at high detection significance, $\gtrsim 5 \sigma$ and $\gtrsim 6 \sigma$, respectively, for the two fiducial radii. The line-of-sight position of the deepest region of the void is $z\simeq 0.15-0.25$. Our data, combined with an earlier measurement by Granett et al. 2010, are consistent with a large $R_{\rm void}=(220 \pm 50) h^{-1}Mpc $ supervoid with $\delta_{m} \simeq -0.14 \pm 0.04$ centered at $z=0.22\pm0.03$. Such a supervoid, constituting at least a $\simeq 3.3\sigma$ fluctuation in a Gaussian distribution of the $\Lambda CDM$ model, is a plausible cause for the Cold Spot., Comment: 8 pages, 6 figures, accepted for publication by MNRAS

We present a new satellite in the outer halo of the Galaxy, the first Milky Way satellite found in the stacked photometric catalog of the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1) Survey. From follow-up photometry obtained with WFI on the MPG/ESO 2.2m telescope, we argue that the object, located at a heliocentric distance of 145+/-17 kpc, is the most distant Milky Way globular cluster yet known. With a total magnitude of M_V=-4.3+/-0.2 and a half-light radius of 20+/-2 pc, it shares the properties of extended globular clusters found in the outer halo of our Galaxy and the Andromeda galaxy. The discovery of this distant cluster shows that the full spatial extent of the Milky Way globular cluster system has not yet been fully explored., Comment: 6 pages, 4 figures, accepted

We present a method to infer reddenings and distances to stars, based only on their broad-band photometry, and show how this method can be used to produce a three-dimensional dust map of the Galaxy. Our method samples from the full probability density function of distance, reddening and stellar type for individual stars, as well as the full uncertainty in reddening as a function of distance in the 3D dust map. We incorporate prior knowledge of the distribution of stars in the Galaxy and the detection limits of the survey. For stars in the Pan-STARRS 1 (PS1) 3 pi survey, we demonstrate that our reddening estimates are unbiased, and accurate to ~0.13 mag in E(B-V) for the typical star. Based on comparisons with mock catalogs, we expect distances for main-sequence stars to be constrained to within ~20% - 60%, although this range can vary, depending on the reddening of the star, the precise stellar type and its position on the sky. A further paper will present a 3D map of dust over the three quarters of the sky surveyed by PS1. Both the individual stellar inferences and the 3D dust map will enable a wealth of Galactic science in the plane. The method we present is not limited to the passbands of the PS1 survey, but may be extended to incorporate photometry from other surveys, such as 2MASS, SDSS (where available), and in the future, LSST and Gaia., Comment: 18 pages, 12 figures

We measure the angular clustering of 33 415 extremely red objects (EROs) in the Elais-N1 field covering 5.33 deg$^{2}$, which cover the redshift range $z=0.8$ to $2$. This sample was made by merging the UKIDSS Deep eXtragalactic Survey (DXS) with the optical Subaru and Pan-STARRS PS1 datasets. We confirm the existence of a clear break in the angular correlation function at $\sim 0.02^{\circ}$ corresponding to $1 h^{-1}$ Mpc at $z\sim1$. We find that redder or brighter EROs are more clustered than bluer or fainter ones. Halo Occupation Distribution (HOD) model fits imply that the average mass of dark matter haloes which host EROs is over $10^{13} h^{-1} M_{\odot}$ and that EROs have a bias ranging from 2.7 to 3.5. Compared to EROs at $z\sim1.1$, at $z\sim1.5$ EROs have a higher bias and fewer are expected to be satellite galaxies. Furthermore, EROs reside in similar dark matter haloes to those that host $10^{11.0} M_{\odot}

We present the discovery of a new dwarf galaxy, Perseus I/Andromeda XXXIII, found in the vicinity of Andromeda (M31) in stacked imaging data from the Pan-STARRS1 3{\pi} survey. Located 27.9{\deg} away from M31, Perseus I has a heliocentric distance of 785 +/- 65 kpc, compatible with it being a satellite of M31 at 374 +14/-10 kpc from its host. The properties of Perseus I are typical for a reasonably bright dwarf galaxy (M_V = -10.3 +/- 0.7), with an exponential half-light radius of r_h = 1.7 +/- 0.4 arcminutes or r_h = 400 +105/-85 pc at this distance, and a moderate ellipticity (\epsilon = 0.43 +0.15/-0.17). The late discovery of Perseus I is due to its fairly low surface brightness (\mu_0=25.7 +1.0/-0.9 mag/arcsec^2), and to the previous lack of deep, high quality photometric data in this region. If confirmed to be a companion of M31, the location of Perseus I, far east from its host, could place interesting constraints on the bulk motion of the satellite system of M31., Comment: 6 pages, 4 figures. Accepted for publication in ApJL

Whatever the school size, the total fees for the International Baccalaureate (IB) are between three and nine times greater than British-style A-level examination fees. There are also indirect administrative, staffing, equipment, and inservice training costs involved. A survey of 18 international schools claims that sound financial management can cut implementation costs. (MLH)