The Magellanic Clouds are a local laboratory for understanding the evolution and properties of dwarf irregular galaxies. To reveal the extended structure and interaction history of the Magellanic Clouds we have undertaken a large-scale photometric and spectroscopic study of their stellar periphery (the MAgellanic Periphery Survey, MAPS). We present first MAPS results for the Small Magellanic Cloud (SMC): Washington M, T-2 + DDO51 photometry reveals metal-poor red giant branch stars in the SMC that extend to large radii (similar to 11 kpc), are distributed nearly azimuthally symmetrically (ellipticity = 0.1), and are well fitted by an exponential profile (out to R approximate to 7 degrees.5). An similar to 6 Gyr old, [Fe/H] approximate to - 1.3 main-sequence turnoff is also evident to at least R = 7 degrees.3, and as far as 8 degrees.4 in some directions. We find evidence for a "break" population beyond similar to 8 radial scale lengths having a very shallow radial density profile that could be either a bound stellar halo or a population of extratidal stars. The distribution of the intermediate stellar component (3 degrees less than or similar to R less than or similar to 7 degrees.5) contrasts with that of the inner stellar component (R less than or similar to 3 degrees), which is both more elliptical (epsilon approximate to 0.3) and offset from the center of the intermediate component by 0 degrees.59, although both components share a similar radial exponential scale length. This offset is likely due to a perspective effect because stars on the eastern side of the SMC are closer on average than stars on the western side. This mapping of its outer stellar structures indicates that the SMC is more complex than previously thought.

A superior mutual event of the Kuiper Belt binary system (79360) Sila-Nunam was observed over 15.47 h on UT 7/8 February 2013 by a coordinated effort at four different telescope facilities; it started similar to 1.5 h earlier than anticipated, the duration was similar to 9.5 h (about 10% longer than predicted), and was slightly less deep than predicted. It is the first full event observed for a comparably sized binary Kuiper Belt object. We provide predictions for future events refined by this and other partial mutual event observations obtained since the mutual event season began. (C) 2013 Elsevier Inc. All rights reserved.

Dark Skies, Bright Kids! (DSBK) is an outreach organization that seeks to enhance elementary-level science literacy and encourage inquiry through fun, hands-on activities. DSBK was formed by, and is operated through, volunteer efforts from professional scientists at all career stages, e.g., from first-year undergraduate students to tenured professors. Although DSBK has amassed over 14,000 contact hours since 2009, there has been no formal evaluation of the programs impacts. Over the past year, DSBK introduced a large-scale, student-led internal assessments program with the systematic evaluation of student workbooks, volunteer surveys, and observations. While the data indicated broad-scale success for the program for both of its goals, it also revealed the organizational and educational practices that not only maximized student achievement, but also created the largest overall volunteer satisfaction with their time commitment. Here we describe DSBK in detail, summarize the student-led implementation of the assessments program, discuss how the results of the assessments have positively impacted our operations, and generalize these results for other scientist-led outreach efforts.

We spectroscopically identify a sample of carbon stars in the satellites and halo of M31 using moderate-resolution optical spectroscopy from the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo survey. We present the photometric properties of our sample of 41 stars, including their brightness with respect to the tip of the red giant branch (TRGB) and their distributions in various color-color spaces. This analysis reveals a bluer population of carbon stars fainter than the TRGB and a redder population of carbon stars brighter than the TRGB. We then apply principal component analysis to determine the sample's eigenspectra and eigencoefficients. Correlating the eigencoefficients with various observable properties reveals the spectral features that trace effective temperature and metallicity. Putting the spectroscopic and photometric information together, we find the carbon stars in the satellites and halo of M31 to be minimally impacted by dust and internal dynamics. We also find that while there is evidence to suggest that the sub-TRGB stars are extrinsic in origin, it is also possible that they are are particularly faint members of the asymptotic giant branch.

A history is given of the discovery between 1914 and 1935 of stars of intermediate luminosity between giants and dwarfs with spectral types between G0 to K3. The Mount Wilson spectroscopists identified about 90 such stars in their 1935 summary paper of spectroscopic absolute magnitudes for 4179 stars. Called "subgiants" by Stromberg, these 90 stars defined the group at the time. The position of the Mount Wilson subgiants in the HR diagram caused difficulties in comparisons of high weight trigonometric parallaxes being measured in the 1930s and with Russell's prevailing evolution proposal, and critics questioned the reality of the Mount Wilson subgiants. To show that the 1935 Mount Wilson subgiants are real, we compare, star-by-star, the Mount Wilson spectroscopic absolute magnitudes of the 90 stars defining their sample against those absolute magnitudes derived from Hipparcos trigonometric parallaxes. We address concerns over biases in the Mount Wilson calibration sample and biases created by the adopted methodology for calibration. Historically, these concerns were sufficient to discredit the discovery of subgiants in the Mount Wilson sample. However, as shown here, the majority of the Mount Wilson stars identified as subgiants that also have reliable Hipparcos trigonometric parallaxes do lie among the subgiant sequence in the Hipparcos HR diagram. Moreover, no significant offset is seen between the M-V brightnesses derived from the Mount Wilson spectroscopic parallaxes and the M-V values derived from Hipparcos trigonometric parallaxes with sigma(pi)/pi < 0.10, which confirms in an impressive manner the efficacy of the original Mount Wilson assessments. The existence of subgiants proved that Russell's contraction proposal for stellar evolution from giants to the main sequence was incorrect. Instead, Gamow's 1944 unpublished conjecture that subgiants are post main-sequence stars just having left the main sequence was very nearly correct but was a decade before its time.

Ultra-faint dwarf galaxies (UFDs) are the faintest known galaxies, and due to their incredibly low surface brightness, it is difficult to find them beyond the Local Group. We report a serendipitous discovery of a UFD, Fornax UFD1, in the outskirts of NGC 1316, a giant galaxy in the Fornax cluster. The new galaxy is located at a projected radius of 55 kpc in the south-east of NGC 1316. This UFD is found as a small group of resolved stars in the Hubble Space Telescope images of a halo field of NGC 1316, obtained as part of the Carnegie-Chicago Hubble Program. Resolved stars in this galaxy are consistent with being mostly metal-poor red giant branch (RGB) stars. Applying the tip of the RGB method to the mean magnitude of the two brightest RGB stars, we estimate the distance to this galaxy, 19.0. +/-. 1.3 Mpc. Fornax UFD1 is probably a member of the Fornax cluster. The color-magnitude diagram of these stars is matched by a 12 Gyr isochrone with low metallicity ([Fe/H]approximate to-2.4). Total magnitude and effective radius of Fornax UFD1 are M-V approximate to -7.6 +/- 0.2 mag and r(eff) = 146 +/- 9 pc, which are similar to those of Virgo UFD1 that was discovered recently in the intracluster field of Virgo by Jang & Lee. Fornax UFD1 is the most distant known UFD that is confirmed by resolved stars. This indicates that UFDs are ubiquitous and that more UFDs remain to be discovered in the Fornax cluster.

We present a proper motion measurement for the halo globular cluster Pyxis, using Hubble Space Telescope/ACS data as the first epoch and GeMS/GSAOI Adaptive Optics data as the second, separated by a baseline of similar to 5 years. This is both the first measurement of the proper motion of Pyxis and the first calibration and use of Multi Conjugate Adaptive Optics data to measure an absolute proper motion for a faint, distant halo object. Consequently, we present our analysis of the Adaptive Optics data in detail. We obtain a proper motion of mu(alpha) cos (delta) = 1.09 +/- 0.31 mas yr(-1) and mu(delta) = 0.68 +/- 0.29 mas yr(-1). From the proper motion and line-of-sight velocity, we find that the orbit of Pyxis is rather eccentric, with its apocenter at more than 100 kpc and its pericenter at about 30 kpc. We also investigate two literature-proposed associations for Pyxis with the recently discovered ATLAS stream and the Magellanic system. Combining our measurements with dynamical modeling and cosmological numerical simulations, we find it unlikely Pyxis is associated with either system. We examine other Milky Way satellites for possible association using the orbit, eccentricity, metallicity, and age as constraints and find no likely matches in satellites down to the mass of Leo II. We propose that Pyxis probably originated in an unknown galaxy, which today is fully disrupted. Assuming that Pyxis is bound and not on a first approach, we derive a 68% lower limit on the mass of the Milky Way of 0.95 x 10(12) M-circle dot.

We present the velocity dispersion of red giant branch stars in M31's halo, derived by modeling the line-of-sight velocity distribution of over 5000 stars in 50 fields spread throughout M31's stellar halo. The data set was obtained as part of the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) Survey, and covers projected radii of 9 to 175 kpc from M31's center. All major structural components along the line of sight in both the Milky Way (MW) and M31 are incorporated in a Gaussian Mixture Model, including all previously identified M31 tidal debris features in the observed fields. The probability that an individual star is a constituent of M31 or the MW, based on a set of empirical photometric and spectroscopic diagnostics, is included as a prior probability in the mixture model. The velocity dispersion of stars in M31's halo is found to decrease only mildly with projected radius, from 108 km s(-1) in the innermost radial bin (8.2 to 14.1 kpc) to similar to 80 to 90 km s(-1) at projected radii of similar to 40-130 kpc, and can be parameterized with a power law of slope -0.12 +/- 0.05. The quoted uncertainty on the power-law slope reflects only the precision of the method, although other sources of uncertainty we consider contribute negligibly to the overall error budget.

We present a new complete near-infrared (NIR, JHK(s)) census of RR Lyrae stars (RRLs) in the globular omega Cen (NGC 5139). We collected 15,472 JHKs images with 4-8 m class telescopes over 15 years (2000-2015) covering a sky area around the cluster center of 60 x 34 arcmin(2). These images provided calibrated photometry for 182 out of the 198 cluster RRL candidates with 10 to 60 measurements per band. We also provide new homogeneous estimates of the photometric amplitude for 180 (J), 176 (H) and 174 (K-s) RRLs. These data were supplemented with single-epoch JK(s) magnitudes from VHS and with single-epoch H magnitudes from 2MASS. Using proprietary optical and NIR data together with new optical light curves (ASAS-SN) we also updated pulsation periods for 59 candidate RRLs. As a whole, we provide JHKs magnitudes for 90 RRab (fundamentals), 103 RRc (first overtones) and one RRd (mixed-mode pulsator). We found that NIR/optical photometric amplitude ratios increase when moving from first overtone to fundamental and to long-period (P > 0.7 days) fundamental RRLs. Using predicted period-luminosity-metallicity relations, we derive a true distance modulus of 13.674 +/- 0.008 +/- 0.038 mag (statistical error and standard deviation of the median) based on spectroscopic iron abundances, and of 13.698 +/- 0.004 +/- 0.048 mag based on photometric iron abundances. We also found evidence of possible systematics at the 5%-10% level in the zero-point of the period-luminosity relations based on the five calibrating RRLs whose parallaxes had been determined with the HST.

The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations.