scholarly journals Prime Focus Spectrograph: A very wide-field, massively multiplexed, optical & near-infrared spectrograph for Subaru Telescope

2015 ◽  
Vol 11 (S319) ◽  
pp. 55-55
Author(s):  
Naoyuki Tamura ◽  
Keyword(s):  
System Integration ◽  
Near Infrared ◽  
Survey Design ◽  
Large Field ◽  
Wide Field ◽  
Chemical Abundances ◽  
Short Article ◽  
The Galaxy ◽  
Galaxy Populations ◽  
Stellar Masses

AbstractThis short article is about Prime Focus Spectrograph (PFS), a very wide-field, massively-multiplexed, and optical & near-infrared (NIR) spectrograph as a next generation facility instrument on Subaru Telescope. More details and updates are available on the PFS official website (http://pfs.ipmu.jp), blog (http://pfs.ipmu.jp/blog/), and references therein.The project, instrument, & timelinePFS will position 2400 fibers to science targets or blank sky in the 1.3 degree field on the Subaru prime focus. These fibers will be quickly (~60sec) reconfigurable and feed the photons during exposures to the Spectrograph System (SpS). SpS consists of 4 modules each of which accommodate ~600 fibers and deliver spectral images ranging from 380nm to 1260nm simultaneously at one exposure via the 3 arms of blue, red, and NIR cameras. The instrument development has been undertaken by the international collaboration at the initiative of Kavli IPMU. The project is now going into the construction phase aiming at system integration and on-sky engineering observations in 2017-2018, and science operation in 2019.The survey design has also been under development envisioning a survey spanning ~300 nights over ~5 years in the framework of Subaru Strategic Program (SSP). The key science areas are: Cosmology, galaxy/AGN evolution, and Galactic Archaeology (GA) (Takada et al. 2014). The cosmology program will be to constrain the nature of dark energy via a survey of emission line galaxies over a comoving volume of 10 Gpc3 at z=0.8-2.4. In the galaxy/AGN program, the wide wavelength coverage of PFS as well as the large field of view will be exploited to characterize the galaxy populations and its clustering properties over a wide redshift range. A survey of color-selected galaxies/AGN at z = 1-2 will be conducted over 20 square degrees yielding a fair sample of galaxies with stellar masses down to ~1010M⊙. In the GA program, radial velocities and chemical abundances of stars in the Milky Way, dwarf spheroids, and M31 will be used to understand the past assembly histories of those galaxies and the structures of their dark matter halos. Spectra will be taken for 1 million stars as faint as V = 22 mag therefore out to large distances from the Sun.PFS will provide powerful spectroscopic capabilities even in the era of Euclid, LSST, WFIRST and TMT, and the effective synergies are expected for further unique science outputs.

scholarly journals The Bimodality of Galaxy Populations Revisited Through Spectral Synthesis

2006 ◽  
Vol 2 (S235) ◽  
pp. 139-139
Author(s):  
L. Sodré ◽  
A. Mateus ◽  
R. Cid Fernandes ◽  
G. Stasińska ◽  
W. Schoenell ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Spectral Synthesis ◽  
Synthesis Method ◽  
Local Universe ◽  
Massive Galaxies ◽  
Star Forming ◽  
The Galaxy ◽  
Galaxy Populations ◽  
Galaxy Population ◽  
Stellar Masses

AbstractWe revisit the bimodality of the galaxy population seen in the local universe. We address this issue in terms of physical properties of galaxies, such as mean stellar ages and stellar masses, derived from the application of a spectral synthesis method to galaxy spectra from the SDSS. We show that the mean light-weighted stellar age of galaxies presents the best description of the bimodality seen in the galaxy population. The stellar mass has an additional role since most of the star-forming galaxies present in the local universe are low-mass galaxies. Our results give support to the existence of a ‘downsizing’ in galaxy formation, where nowadays massive galaxies tend to have stellar populations older than those found in less massive objects.

scholarly journals Euclid preparation

2020 ◽  
Vol 642 ◽  
pp. A192 ◽  
Author(s):  
◽  
V. Guglielmo ◽  
R. Saglia ◽  
F. J. Castander ◽  
A. Galametz ◽  
...  
Keyword(s):  
Near Infrared ◽  
Current Knowledge ◽  
High Redshift ◽  
Stage Iv ◽  
Weak Lensing ◽  
Success Rates ◽  
Spectroscopic Measurements ◽  
Star Forming ◽  
The Galaxy ◽  
Stellar Masses

The Complete Calibration of the Colour–Redshift Relation survey (C3R2) is a spectroscopic effort involving ESO and Keck facilities designed specifically to empirically calibrate the galaxy colour–redshift relation – P(z|C) to the Euclid depth (iAB = 24.5) and is intimately linked to the success of upcoming Stage IV dark energy missions based on weak lensing cosmology. The aim is to build a spectroscopic calibration sample that is as representative as possible of the galaxies of the Euclid weak lensing sample. In order to minimise the number of spectroscopic observations necessary to fill the gaps in current knowledge of the P(z|C), self-organising map (SOM) representations of the galaxy colour space have been constructed. Here we present the first results of an ESO@VLT Large Programme approved in the context of C3R2, which makes use of the two VLT optical and near-infrared multi-object spectrographs, FORS2 and KMOS. This data release paper focuses on high-quality spectroscopic redshifts of high-redshift galaxies observed with the KMOS spectrograph in the near-infrared H- and K-bands. A total of 424 highly-reliable redshifts are measured in the 1.3 ≤ z ≤ 2.5 range, with total success rates of 60.7% in the H-band and 32.8% in the K-band. The newly determined redshifts fill 55% of high (mainly regions with no spectroscopic measurements) and 35% of lower (regions with low-resolution/low-quality spectroscopic measurements) priority empty SOM grid cells. We measured Hα fluxes in a 1.″2 radius aperture from the spectra of the spectroscopically confirmed galaxies and converted them into star formation rates. In addition, we performed an SED fitting analysis on the same sample in order to derive stellar masses, E(B − V), total magnitudes, and SFRs. We combine the results obtained from the spectra with those derived via SED fitting, and we show that the spectroscopic failures come from either weakly star-forming galaxies (at z <  1.7, i.e. in the H-band) or low S/N spectra (in the K-band) of z >  2 galaxies.

scholarly journals Milky Way demographics with the VVV survey

2018 ◽  
Vol 619 ◽  
pp. A4 ◽  
Author(s):  
Javier Alonso-García ◽  
Roberto K. Saito ◽  
Maren Hempel ◽  
Dante Minniti ◽  
Joyce Pullen ◽  
...  
Keyword(s):  
Near Infrared ◽  
Milky Way ◽  
Stellar Populations ◽  
Wide Field ◽  
Public Survey ◽  
Wide Field Of View ◽  
Spread Function ◽  
The Galaxy ◽  
Infrared Wavelengths ◽  
Galactic Stellar Populations

Context. The inner regions of the Galaxy are severely affected by extinction, which limits our capability to study the stellar populations present there. The Vista Variables in the Vía Láctea (VVV) ESO Public Survey has observed this zone at near-infrared wavelengths where reddening is highly diminished. Aims. By exploiting the high resolution and wide field-of-view of the VVV images we aim to produce a deep, homogeneous, and highly complete database of sources that cover the innermost regions of our Galaxy. Methods. To better deal with the high crowding in the surveyed areas, we have used point spread function (PSF)-fitting techniques to obtain a new photometry of the VVV images, in the ZY JHKs near-infrared filters available. Results. Our final catalogs contain close to one billion sources, with precise photometry in up to five near-infrared filters, and they are already being used to provide an unprecedented view of the inner Galactic stellar populations. We make these catalogs publicly available to the community. Our catalogs allow us to build the VVV giga-CMD, a series of color-magnitude diagrams of the inner regions of the Milky Way presented as supplementary videos. We provide a qualitative analysis of some representative CMDs of the inner regions of the Galaxy, and briefly mention some of the studies we have developed with this new dataset so far.

scholarly journals Simulating JWST deep extragalactic imaging surveys and physical parameter recovery

2020 ◽  
Vol 640 ◽  
pp. A67
Author(s):  
O. B. Kauffmann ◽  
O. Le Fèvre ◽  
O. Ilbert ◽  
J. Chevallard ◽  
C. C. Williams ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Spectral Energy ◽  
Photometric Redshifts ◽  
The Galaxy ◽  
Stellar Masses ◽  
The Impact

We present a new prospective analysis of deep multi-band imaging with the James Webb Space Telescope (JWST). In this work, we investigate the recovery of high-redshift 5 <  z <  12 galaxies through extensive image simulations of accepted JWST programs, including the Early Release Science in the EGS field and the Guaranteed Time Observations in the HUDF. We introduced complete samples of ∼300 000 galaxies with stellar masses of log(M*/M⊙) > 6 and redshifts of 0 <  z <  15, as well as galactic stars, into realistic mock NIRCam, MIRI, and HST images to properly describe the impact of source blending. We extracted the photometry of the detected sources, as in real images, and estimated the physical properties of galaxies through spectral energy distribution fitting. We find that the photometric redshifts are primarily limited by the availability of blue-band and near-infrared medium-band imaging. The stellar masses and star formation rates are recovered within 0.25 and 0.3 dex, respectively, for galaxies with accurate photometric redshifts. Brown dwarfs contaminating the z >  5 galaxy samples can be reduced to < 0.01 arcmin−2 with a limited impact on galaxy completeness. We investigate multiple high-redshift galaxy selection techniques and find that the best compromise between completeness and purity at 5 <  z <  10 using the full redshift posterior probability distributions. In the EGS field, the galaxy completeness remains higher than 50% at magnitudes mUV <  27.5 and at all redshifts, and the purity is maintained above 80 and 60% at z ≤ 7 and 10, respectively. The faint-end slope of the galaxy UV luminosity function is recovered with a precision of 0.1–0.25, and the cosmic star formation rate density within 0.1 dex. We argue in favor of additional observing programs covering larger areas to better constrain the bright end.

scholarly journals Observational constraints on the optical and near-infrared emission from the neutron star–black hole binary merger candidate S190814bv

2020 ◽  
Vol 643 ◽  
pp. A113 ◽  
Author(s):  
K. Ackley ◽  
L. Amati ◽  
C. Barbieri ◽  
F. E. Bauer ◽  
S. Benetti ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Near Infrared ◽  
Large Fraction ◽  
High Sensitivity ◽  
Infrared Emission ◽  
Large Field ◽  
Wide Field ◽  
Targeted Observations

Context. Gravitational wave (GW) astronomy has rapidly reached maturity, becoming a fundamental observing window for modern astrophysics. The coalescences of a few tens of black hole (BH) binaries have been detected, while the number of events possibly including a neutron star (NS) is still limited to a few. On 2019 August 14, the LIGO and Virgo interferometers detected a high-significance event labelled S190814bv. A preliminary analysis of the GW data suggests that the event was likely due to the merger of a compact binary system formed by a BH and a NS. Aims. In this paper, we present our extensive search campaign aimed at uncovering the potential optical and near infrared electromagnetic counterpart of S190814bv. We found no convincing electromagnetic counterpart in our data. We therefore use our non-detection to place limits on the properties of the putative outflows that could have been produced by the binary during and after the merger. Methods. Thanks to the three-detector observation of S190814bv, and given the characteristics of the signal, the LIGO and Virgo Collaborations delivered a relatively narrow localisation in low latency – a 50% (90%) credible area of 5 deg2 (23 deg2) – despite the relatively large distance of 267 ± 52 Mpc. ElectromagNetic counterparts of GRAvitational wave sources at the VEry Large Telescope collaboration members carried out an intensive multi-epoch, multi-instrument observational campaign to identify the possible optical and near infrared counterpart of the event. In addition, the ATLAS, GOTO, GRAWITA-VST, Pan-STARRS, and VINROUGE projects also carried out a search on this event. In this paper, we describe the combined observational campaign of these groups. Results. Our observations allow us to place limits on the presence of any counterpart and discuss the implications for the kilonova (KN), which was possibly generated by this NS–BH merger, and for the strategy of future searches. The typical depth of our wide-field observations, which cover most of the projected sky localisation probability (up to 99.8%, depending on the night and filter considered), is r ∼ 22 (resp. K ∼ 21) in the optical (resp. near infrared). We reach deeper limits in a subset of our galaxy-targeted observations, which cover a total ∼50% of the galaxy-mass-weighted localisation probability. Altogether, our observations allow us to exclude a KN with large ejecta mass M ≳ 0.1 M⊙ to a high (> 90%) confidence, and we can exclude much smaller masses in a sub-sample of our observations. This disfavours the tidal disruption of the neutron star during the merger. Conclusions. Despite the sensitive instruments involved in the campaign, given the distance of S190814bv, we could not reach sufficiently deep limits to constrain a KN comparable in luminosity to AT 2017gfo on a large fraction of the localisation probability. This suggests that future (likely common) events at a few hundred megaparsecs will be detected only by large facilities with both a high sensitivity and large field of view. Galaxy-targeted observations can reach the needed depth over a relevant portion of the localisation probability with a smaller investment of resources, but the number of galaxies to be targeted in order to get a fairly complete coverage is large, even in the case of a localisation as good as that of this event.

scholarly journals Searches for Population III pair-instability supernovae: Predictions for ULTIMATE-Subaru and WFIRST

2019 ◽  
Vol 71 (3) ◽  
Author(s):  
Takashi J Moriya ◽  
Kenneth C Wong ◽  
Yusei Koyama ◽  
Masaomi Tanaka ◽  
Masamune Oguri ◽  
...  
Keyword(s):  
First Generation ◽  
Near Infrared ◽  
Field Of View ◽  
Large Field ◽  
Wide Field ◽  
Clusters Of Galaxies ◽  
Infra Red ◽  
Infrared Wavelengths ◽  
Infrared Instruments ◽  
Population Iii

Abstract ULTIMATE-Subaru (Ultra-wide Laser Tomographic Imager and MOS with AO for Transcendent Exploration on Subaru) and WFIRST (Wide Field Infra-Red Survey Telescope) are the next generation of near-infrared instruments that have a large field-of-view. They allow us to conduct deep and wide transient surveys in the near-infrared. Such a near-infrared transient survey enables us to find very distant supernovae that are redshifted to the near-infrared wavelengths. We have performed mock transient surveys with ULTIMATE-Subaru and WFIRST to investigate their ability to discover Population III pair-instability supernovae. We found that a five-year 1 deg2K-band transient survey with a point-source limiting magnitude of 26.5 mag with ULTIMATE-Subaru may find about two Population III pair-instability supernovae beyond the redshift of 6. A five-year 10 deg2 survey with WFIRST reaching 26.5 mag in the F184 band may find about seven Population III pair-instability supernovae beyond the redshift of 6. We also find that the expected numbers of the Population III pair-instability supernova detections increase by about a factor of 2 if the near-infrared transient surveys are performed towards clusters of galaxies. Other supernovae, such as Population II pair-instability supernovae, would also be detected in the same survey. This study demonstrates that these future wide-field near-infrared instruments allow us to investigate the explosions of first-generation supernovae by performing deep and wide near-infrared transient surveys.

scholarly journals The VIMOS Public Extragalactic Redshift Survey (VIPERS)

2018 ◽  
Vol 617 ◽  
pp. A70 ◽  
Author(s):  
M. Siudek ◽  
K. Małek ◽  
A. Pollo ◽  
T. Krakowski ◽  
A. Iovino ◽  
...  
Keyword(s):  
Rest Frame ◽  
Near Infrared ◽  
Spectroscopic Properties ◽  
Joint Analysis ◽  
Spectral Energy ◽  
New Approach ◽  
The Galaxy ◽  
Galaxy Populations ◽  
Galaxy Classification ◽  
Number Of Classes

Aims. Various galaxy classification schemes have been developed so far to constrain the main physical processes regulating evolution of different galaxy types. In the era of a deluge of astrophysical information and recent progress in machine learning, a new approach to galaxy classification has become imperative. Methods. In this paper, we employ a Fisher Expectation-Maximization (FEM) unsupervised algorithm working in a parameter space of 12 rest-frame magnitudes and spectroscopic redshift. The model (DBk) and the number of classes (12) were established based on the joint analysis of standard statistical criteria and confirmed by the analysis of the galaxy distribution with respect to a number of classes and their properties. This new approach allows us to classify galaxies based on only their redshifts and ultraviolet to near-infrared (UV–NIR) spectral energy distributions. Results. The FEM unsupervised algorithm has automatically distinguished 12 classes: 11 classes of VIPERS galaxies and an additional class of broad-line active galactic nuclei (AGNs). After a first broad division into blue, green, and red categories, we obtained a further sub-division into: three red, three green, and five blue galaxy classes. The FEM classes follow the galaxy sequence from the earliest to the latest types, which is reflected in their colours (which are constructed from rest-frame magnitudes used in the classification procedure) but also their morphological, physical, and spectroscopic properties (not included in the classification scheme). We demonstrate that the members of each class share similar physical and spectral properties. In particular, we are able to find three different classes of red passive galaxy populations. Thus, we demonstrate the potential of an unsupervised approach to galaxy classification and we retrieve the complexity of galaxy populations at z ∼ 0.7, a task that usual, simpler, colour-based approaches cannot fulfil.

scholarly journals Semi-analytic forecasts for JWST – IV. Implications for cosmic reionization and LyC escape fraction

2020 ◽  
Vol 496 (4) ◽  
pp. 4574-4592 ◽  
Author(s):  
L Y Aaron Yung ◽  
Rachel S Somerville ◽  
Steven L Finkelstein ◽  
Gergö Popping ◽  
Romeel Davé ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Near Infrared ◽  
Infrared Camera ◽  
Ground Level ◽  
Big Bang ◽  
Computationally Efficient ◽  
James Webb Space Telescope ◽  
The Galaxy ◽  
Low Mass ◽  
Galaxy Populations

ABSTRACT Galaxies forming in low-mass haloes are thought to be primarily responsible for reionizing the Universe during the first billion years after the big bang. Yet, these haloes are extremely inefficient at forming stars in the nearby Universe. In this work, we address this apparent tension, and ask whether a physically motivated model of galaxy formation that reproduces the observed abundance of faint galaxies in the nearby Universe is also consistent with available observational constraints on the reionization history. By interfacing the Santa Cruz semi-analytic model for galaxy formation with an analytic reionization model, we constructed a computationally efficient pipeline that connects ‘ground-level’ galaxy formation physics to ‘top-level’ cosmological-scale observables. Based on photometric properties of the galaxy populations predicted up to z = 15, we compute the reionization history of intergalactic hydrogen. We quantify the three degenerate quantities that influence the total ionizing photon budget, including the abundance of galaxies, the intrinsic production rate of ionizing photons, and the LyC escape fraction. We explore covariances between these quantities using a Markov chain Monte Carlo method. We find that our locally calibrated model is consistent with all currently available constraints on the reionization history, under reasonable assumptions about the LyC escape fraction. We quantify the fraction of ionizing photons produced by galaxies of different luminosities and find that the galaxies expected to be detected in James Webb Space Telescope Near-Infrared Camera (NIRCam) wide and deep surveys are responsible for producing ∼40–80 per cent of ionizing photons throughout the Epoch of Reionization. All results presented in this work are available at https://www.simonsfoundation.org/semi-analytic-forecasts-for-jwst/.

scholarly journals Global Properties of Nearby Galaxies

1994 ◽  
Vol 161 ◽  
pp. 559-566
Author(s):  
M. Capaccioli ◽  
N. Caon ◽  
M. D'onofrio
Keyword(s):  
Growth Curves ◽  
Large Field ◽  
Medium Size ◽  
Wide Field ◽  
Surface Photometry ◽  
Indirect Methods ◽  
Research Areas ◽  
The Galaxy ◽  
Nearby Galaxies ◽  
Light Profiles

Surface photometry of nearby galaxies is among the research areas that gained most from the recent advances in ‘wide-field imaging’. In fact, the demand for an accurate measure of the night-sky level all around the target galaxy — a key step in galaxy surface photometry; see Fig. 1 in Capaccioli &amp; de Vaucouleurs (1983) — calls for at least some images covering a field wider than the size of the object under study. So far, the small field of most CCD cameras attached to the Cassegrain foci of medium-size telescopes has prevented both the mapping of the galaxian outskirts and, a fortiori, a direct measurement of the sky background μs on the galaxy image itself. Indirect methods to estimate μs — blank-sky exposures, matching of growth curves to photoelectric integrated magnitudes, assumptions on the shape of the galaxian light profiles — have proven ineffective and/or methodologically questionable (Capaccioli 1989). Until large-format CCD chips or mosaics are routinely used, the only way out of these problems is either the use of focal reducers, whose optical complexity may however be incompatible with photometric accuracy, or of large-field photographic plates.

scholarly journals A Large Near-Infrared Image of the Galactic Center

1989 ◽  
Vol 136 ◽  
pp. 361-364 ◽  
Author(s):  
Ian Gatley ◽  
R. Joyce ◽  
A. Fowler ◽  
D. Depoy ◽  
R. Probst
Keyword(s):  
Near Infrared ◽  
Galactic Center ◽  
Infrared Image ◽  
Large Field ◽  
Array Detector ◽  
Diode Array ◽  
Diode Array Detector ◽  
Color Picture ◽  
The Galaxy ◽  
Band Image

We have obtained a K band image of the central 30 × 40 arcminutes of the Galaxy at a scale of 1.4″/pixel using a 256 × 256 Pt: Si Schottky barrier diode array detector provided by the Hughes Aircraft Company. The excellent cosmetic quality and large field of this device provide an unprecedented view of the inner Galaxy. Images of the central 10 arcminutes at a scale of 0.9″/pixel in the H (1.65μm) and K (2.2μm) bands produced with the same detector array have been combined to produce a color picture, which clearly shows the circumnuclear molecular ring in absorption; this picture demonstrates directly that the southwestern side of the ring lies in front of, and the northeastern side behind, the Galactic center.

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