scholarly journals The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

2009 ◽  
Vol 5 (S262) ◽  
pp. 428-429
Author(s):  
Ricardo P. Schiavon ◽  
Steven R. Majewski
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Milky Way ◽  
Galactic Evolution ◽  
Sloan Digital Sky Survey ◽  
Elemental Abundances ◽  
Sky Survey ◽  
The Galaxy ◽  
Evolution Experiment ◽  
Under Construction

AbstractThe Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a large scale, high-resolution, near-infrared spectroscopic survey of Milky Way stellar populations and one of the four experiments in the Sloan Digital Sky Survey III (SDSS-III). APOGEE will be based on a new multi-fiber cryogenic spectrograph, currently under construction, expected to begin survey observations on the 2.5 m Sloan telescope in the Spring of 2011. APOGEE will measure high-precision radial velocities and elemental abundances for ~15 elements for ~ 105 stars, and is expected to shed new light on the processes that led to the formation of the Galaxy.

scholarly journals The Apache Point Observatory Galactic Evolution Experiment (APOGEE) in Sloan Digital Sky Survey III (SDSS-III)

2009 ◽  
Vol 5 (S265) ◽  
pp. 480-481 ◽  
Author(s):  
Steven R. Majewski ◽  
John C. Wilson ◽  
Fred Hearty ◽  
Ricardo R. Schiavon ◽  
Michael F. Skrutskie
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Milky Way ◽  
Chemical Species ◽  
Galactic Evolution ◽  
Sloan Digital Sky Survey ◽  
Red Giants ◽  
Sky Survey ◽  
Evolution Experiment ◽  
Novel Design

AbstractThe Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a large-scale, near-infrared (H-band), high-resolution (R ~ 30,000), high S/N (≳100) spectroscopic survey of Milky Way stellar populations. APOGEE will operate from 1.51–1.68μm, a region that includes useful absorption lines from at least fifteen chemical species including α, odd-Z, and iron peak elements. The APOGEE instrument has a novel design featuring 300 science fibers feeding light to a mosaiced VPH grating and a six-element camera encased in a liquid nitrogen-cooled cryostat. A three year bright-time observing campaign will enable APOGEE to observe approximately 100,000 red giants across the Galactic bulge, disk and halo.

scholarly journals SEGUE, and the future of large scale surveys of the Galaxy

2008 ◽  
Vol 4 (S254) ◽  
pp. 461-468
Author(s):  
Timothy C. Beers ◽  
Young Sun Lee ◽  
Daniela Carollo
Keyword(s):  
Large Scale ◽  
Milky Way ◽  
Sloan Digital Sky Survey ◽  
Atmospheric Parameters ◽  
Near Ir ◽  
Medium Resolution ◽  
Sky Survey ◽  
The Galaxy ◽  
Scientific Results

AbstractThe Sloan Extension for Galactic Exploration and Understanding (SEGUE) has now been completed. This is one of three surveys that were executed as part of the first extension of the Sloan Digital Sky Survey (SDSS-II), which consist of LEGACY, SUPERNOVA SURVEY, and SEGUE. The SEGUE program has obtained over 3600 square degrees of ugriz imaging of the sky outside the original SDSS-I footprint. The regions of sky targeted for SEGUE imaging were primarily at lower Galactic latitudes (|b| < 35°), in order to better sample the disk/halo interface of the Milky Way. SEGUE also obtained medium-resolution (R = 2000) spectroscopy, over the wavelength range 3800-9200 Å, for over 200,000 stars in 200 selected areas over the sky available from Apache Point, New Mexico. We discuss the determination of stellar atmospheric parameters (Teff, log g, and [Fe/H]) for these stars, and highlight several of the scientific results obtained to date. The proposed second extension of SDSS, known as SDSS-III, will include SEGUE-2, a program to roughly double the numbers of stars with available spectroscopy, as well as APOGEE, a program to obtain high-resolution (R = 20000) near-IR spectroscopy for over 100,000 stars in the disk, bulge and halo populations of the Galaxy. Other massive spectroscopic surveys of interest to Galactic science are also briefly discussed.

scholarly journals Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey

2021 ◽  
Vol 162 (6) ◽  
pp. 302
Author(s):  
Rachael L. Beaton ◽  
Ryan J. Oelkers ◽  
Christian R. Hayes ◽  
Kevin R. Covey ◽  
S. D. Chojnowski ◽  
...  
Keyword(s):  
Near Infrared ◽  
Survey Design ◽  
Target Selection ◽  
Lessons Learned ◽  
Galactic Evolution ◽  
Sloan Digital Sky Survey ◽  
Scientific Success ◽  
Sky Survey ◽  
Evolution Experiment ◽  
Targeting Strategy

Abstract The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing a chemodynamical mapping of the Milky Way. The targeting for APOGEE-2 is complex and has evolved with time. In this paper, we present the updates and additions to the initial targeting strategy for APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two implementation modes: (i) “Ancillary Science Programs” competitively awarded to Sloan Digital Sky Survey IV PIs through proposal calls in 2015 and 2017 for the pursuit of new scientific avenues outside the main survey, and (ii) an effective 1.5 yr expansion of the survey, known as the Bright Time Extension (BTX), made possible through accrued efficiency gains over the first years of the APOGEE-2N project. For the 23 distinct ancillary programs, we provide descriptions of the scientific aims, target selection, and how to identify these targets within the APOGEE-2 sample. The BTX permitted changes to the main survey strategy, the inclusion of new programs in response to scientific discoveries or to exploit major new data sets not available at the outset of the survey design, and expansions of existing programs to enhance their scientific success and reach. After describing the motivations, implementation, and assessment of these programs, we also leave a summary of lessons learned from nearly a decade of APOGEE-1 and APOGEE-2 survey operations. A companion paper, F. Santana et al. (submitted; AAS29036), provides a complementary presentation of targeting modifications relevant to APOGEE-2 operations in the Southern Hemisphere.

scholarly journals A study on the statistical significance of mutual information between morphology of a galaxy and its large-scale environment

2020 ◽  
Vol 497 (4) ◽  
pp. 4077-4090 ◽  
Author(s):  
Suman Sarkar ◽  
Biswajit Pandey
Keyword(s):  
Mutual Information ◽  
Large Scale ◽  
Statistical Significance ◽  
Sloan Digital Sky Survey ◽  
Data Sets ◽  
Information Theoretic ◽  
Galaxy Distribution ◽  
Sky Survey ◽  
The Galaxy ◽  
Physical Correlations

ABSTRACT A non-zero mutual information between morphology of a galaxy and its large-scale environment is known to exist in Sloan Digital Sky Survey (SDSS) upto a few tens of Mpc. It is important to test the statistical significance of these mutual information if any. We propose three different methods to test the statistical significance of these non-zero mutual information and apply them to SDSS and Millennium run simulation. We randomize the morphological information of SDSS galaxies without affecting their spatial distribution and compare the mutual information in the original and randomized data sets. We also divide the galaxy distribution into smaller subcubes and randomly shuffle them many times keeping the morphological information of galaxies intact. We compare the mutual information in the original SDSS data and its shuffled realizations for different shuffling lengths. Using a t-test, we find that a small but statistically significant (at $99.9{{\ \rm per\ cent}}$ confidence level) mutual information between morphology and environment exists upto the entire length-scale probed. We also conduct another experiment using mock data sets from a semi-analytic galaxy catalogue where we assign morphology to galaxies in a controlled manner based on the density at their locations. The experiment clearly demonstrates that mutual information can effectively capture the physical correlations between morphology and environment. Our analysis suggests that physical association between morphology and environment may extend to much larger length-scales than currently believed, and the information theoretic framework presented here can serve as a sensitive and useful probe of the assembly bias and large-scale environmental dependence of galaxy properties.

scholarly journals Finding and characterising WHIM structures using the luminosity density method

2014 ◽  
Vol 11 (S308) ◽  
pp. 368-371
Author(s):  
Jukka Nevalainen ◽  
L. J. Liivamägi ◽  
E. Tempel ◽  
E. Branchini ◽  
M. Roncarelli ◽  
...  
Keyword(s):  
Large Scale ◽  
Real Data ◽  
Sloan Digital Sky Survey ◽  
Physical Parameters ◽  
X Ray ◽  
Galaxy Surveys ◽  
Sky Survey ◽  
The Galaxy ◽  
Hydrodynamical Simulations ◽  
X Ray Absorption

AbstractWe have developed a new method to approach the missing baryons problem. We assume that the missing baryons reside in a form of Warm Hot Intergalactic Medium, i.e. the WHIM. Our method consists of (a) detecting the coherent large scale structure in the spatial distribution of galaxies that traces the Cosmic Web and that in hydrodynamical simulations is associated to the WHIM, (b) mapping its luminosity into a galaxy luminosity density field, (c) using numerical simulations to relate the luminosity density to the density of the WHIM, (d) applying this relation to real data to trace the WHIM using the observed galaxy luminosities in the Sloan Digital Sky Survey and 2dF redshift surveys. In our application we find evidence for the WHIM along the line of sight to the Sculptor Wall, at redshifts consistent with the recently reported X-ray absorption line detections. Our indirect WHIM detection technique complements the standard method based on the detection of characteristic X-ray absorption lines, showing that the galaxy luminosity density is a reliable signpost for the WHIM. For this reason, our method could be applied to current galaxy surveys to optimise the observational strategies for detecting and studying the WHIM and its properties. Our estimates of the WHIM hydrogen column density NH in Sculptor agree with those obtained via the X-ray analysis. Due to the additional NH estimate, our method has potential for improving the constrains of the physical parameters of the WHIM as derived with X-ray absorption, and thus for improving the understanding of the missing baryons problem.

APOGEE: the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment. Insights into the Galactic Disk: A Review

2017 ◽  
Vol 13 (S334) ◽  
pp. 101-108
Author(s):  
Jon A. Holtzman ◽  
Sten Hasselquist ◽  
Keyword(s):  
Galactic Disk ◽  
Structural Parameters ◽  
Distribution Functions ◽  
Galactic Evolution ◽  
Sloan Digital Sky Survey ◽  
Element Abundance ◽  
Near Ir ◽  
Stellar Ages ◽  
Sky Survey ◽  
Evolution Experiment

AbstractThe SDSS Apache Point Observatory Galactic Evolution Experiment (APOGEE) has collected high resolution near-IR spectra for several hundred thousand stars throughout the Milky Way. We review some of the results related to chemistry of stars in the disk, where APOGEE has a particular advantage by virtue of being able to work in more obscured areas. The ability to measure carbon and nitrogen abundances in giants in the near-IR provides insight into stellar ages. We summarize results on the variation of mean metallicity, metallicity distribution functions, and the [α/Fe]–[Fe/H] relation across the Galactic disk, as well as results on the structural parameters in mono-abundance populations. Many of these results suggest that radial migration has played a significant role in the Galactic disk. It may be possible to disentangle radial mixing using multi-element abundance patterns.

scholarly journals Characterising filaments in the SDSS volume from the galaxy distribution

2020 ◽  
Vol 642 ◽  
pp. A19 ◽  
Author(s):  
Nicola Malavasi ◽  
Nabila Aghanim ◽  
Marian Douspis ◽  
Hideki Tanimura ◽  
Victor Bonjean
Keyword(s):  
Large Scale ◽  
Sloan Digital Sky Survey ◽  
Specific Method ◽  
Redshift Surveys ◽  
Galaxy Distribution ◽  
Systematic Uncertainties ◽  
Sky Survey ◽  
The Galaxy ◽  
Free Parameters ◽  
The Universe

Detecting the large-scale structure of the Universe based on the galaxy distribution and characterising its components is of fundamental importance in astrophysics but is also a difficult task to achieve. Wide-area spectroscopic redshift surveys are required to accurately measure galaxy positions in space that also need to cover large areas of the sky. It is also difficult to create algorithms that can extract cosmic web structures (e.g. filaments). Moreover, these detections will be affected by systematic uncertainties that stem from the characteristics of the survey used (e.g. its completeness and coverage) and from the unique properties of the specific method adopted to detect the cosmic web (i.e. the assumptions it relies on and the free parameters it may employ). For these reasons, the creation of new catalogues of cosmic web features on wide sky areas is important, as this allows users to have at their disposal a well-understood sample of structures whose systematic uncertainties have been thoroughly investigated. In this paper we present the filament catalogues created using the discrete persistent structure extractor tool in the Sloan Digital Sky Survey (SDSS), and we fully characterise them in terms of their dependence on the choice of parameters pertaining to the algorithm, and with respect to several systematic issues that may arise in the skeleton as a result of the properties of the galaxy distribution (such as Finger-of-God redshift distortions and defects of the density field that are due to the boundaries of the survey).

scholarly journals THE TENTH DATA RELEASE OF THE SLOAN DIGITAL SKY SURVEY: FIRST SPECTROSCOPIC DATA FROM THE SDSS-III APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT

2014 ◽  
Vol 211 (2) ◽  
pp. 17 ◽  
Author(s):  
Christopher P. Ahn ◽  
Rachael Alexandroff ◽  
Carlos Allende Prieto ◽  
Friedrich Anders ◽  
Scott F. Anderson ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Galactic Evolution ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
Data Release ◽  
Evolution Experiment

scholarly journals Detecting multi-scale filaments in galaxy distribution

2014 ◽  
Vol 10 (S306) ◽  
pp. 45-47
Author(s):  
Elmo Tempel
Keyword(s):  
Point Process ◽  
Large Scale ◽  
Three Dimensional ◽  
Sloan Digital Sky Survey ◽  
Point Distribution ◽  
Multi Scale ◽  
Galaxy Distribution ◽  
Sky Survey ◽  
The Galaxy ◽  
Redshift Survey

AbstractThe main feature of the spatial large-scale galaxy distribution is its intricate network of galaxy filaments. This network is spanned by the galaxy locations that can be interpreted as a three-dimensional point distribution. The global properties of the point process can be measured by different statistical methods, which, however, do not describe directly the structure elements. The morphology of the large-scale structure, on the other hand, is an important property of the galaxy distribution. Here, we apply an object point process with interactions (the Bisous model) to trace and extract the filamentary network in the presently largest galaxy redshift survey, the Sloan Digital Sky Survey (SDSS data release 10). We search for multi-scale filaments in the galaxy distribution that have a radius of about 0.5, 1.0, 2.0, and 4.0h−1Mpc. We extract the spines of the filamentary network and divide the detected network into single filaments.

scholarly journals DENIS Observations of Multibeam Galaxies in the Zone of Avoidance

1999 ◽  
Vol 16 (1) ◽  
pp. 42-47 ◽  
Author(s):  
A. Schröder ◽  
R. C. Kraan-Korteweg ◽  
G. A. Mamon
Keyword(s):  
Velocity Field ◽  
Large Scale ◽  
Near Infrared ◽  
Milky Way ◽  
Selection Effects ◽  
Galaxy Distribution ◽  
The Galaxy ◽  
Multi Wavelength ◽  
Zone Of Avoidance ◽  
Fisher Relation

AbstractRoughly 25% of the optical extragalactic sky is obscured by the dust and stars of our Milky Way. Dynamically important structures might still lie hidden in this zone. Various surveys are presently being employed to uncover the galaxy distribution in the Zone of Avoidance (ZOA), but all suffer from (different) limitations and selection effects. We illustrate the promise of using a multi-wavelength approach for extragalactic large-scale studies behind the ZOA, i.e. a combination of three surveys, optical, systematic blind HI and near-infrared (NIR), which will allow the mapping of the peculiar velocity field in the ZOA through the NIR Tully–Fisher relation. In particular, we present here the results of cross-identifying HI-detected galaxies with the DENIS NIR survey, and the use of NIR colours to determine foreground extinctions.

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