Abstract
We have developed an automated quick data analysis system for data quality assurance (QA) for Hyper Suprime-Cam (HSC). The system was commissioned in 2012–2014, and has been offered for ...general observations, including the HSC Subaru Strategic Program, since 2014 March. The system provides observers with data quality information, such as seeing, sky background level, and sky transparency, based on quick analysis as data are acquired. Quick-look images and validation of image focus are also provided through an interactive web application. The system is responsible for the automatic extraction of QA information from acquired raw data into a database, to assist with observation planning, assess progress of all observing programs, and monitor long-term efficiency variations of the instrument and telescope. Enhancements of the system are being planned to facilitate final data analysis, to improve the HSC archive, and to provide legacy products for astronomical communities.
We present multi-wave band optical Imaging data obtained from observations of the Subaru/XMM-Newton Deep Survey (SXDS). The survey field, centered at R.A. = 02 super(h) unk 00 super(9), decl. = -05 ...degree 00'00", has been the focus of a wide range of multiwavelength observing programs spanning from X-ray to radio wavelengths. A large part of the optical imaging observations are carried out with Suprime-Cam on Subaru Telescope at Mauna Kea in the course of Subaru Telescope "Observatory Projects." This paper describes our optical observations, data reduction and analysis procedures employed, and the characteristics of the data products. A total area of 1.22 deg super(2) is covered in five contiguous subfields, each of which corresponds to a single Suprime-Cam field of view ( similar to 34' x 27'), in five broadband filters, B, V, Rc, i', and z', to the depths of B = 28.4, V = 27.8, R sub(e) = 27.7, unk = 27.7, and unk=26.6, respectively (AB, 3 sigma ,oe = 2"). The data are reduced and complied into five multi-wave band photometric catalogs, separately for each Suprime-Cam pointing. The i'-band catalogs contain about 900,000 objects, making the SXDS catalogs one of the largest multi-wave band catalogs in corresponding depth and area coverage. The SXDS catalogs can be used for an extensive range of astronomical applications such as the number density of the Galactic halo stars to the large-scale structures at the distant universe. The number counts of galaxies are derived and compared with those of existing deep extragalactic surveys. The optical data, the source catalogs, and configuration files used to create the catalogs are publicly available via the SXDS Web page.
We perform a high-cadence transient survey with the Subaru Hyper Suprime-Cam (HSC), which we call the Subaru HSC survey Optimized for Optical Transients (SHOOT). We conduct HSC imaging observations ...with time intervals of about one hour on two successive nights, and spectroscopic and photometric follow-up observations. A rapidly declining blue transient SHOOT14di at z = 0.4229 is found in observations on two successive nights using an image-subtraction technique. The rate of brightness change is ( ) in the observer (rest) frame and the rest-frame color between 3400 and 4400 is . The nature of the object is investigated by comparing its peak luminosity, decline rate, and color with those of transients and variables previously observed, and with those of theoretical models. None of the transients or variables share the same properties as SHOOT14di. Comparisons with theoretical models demonstrate that, while the emission from the cooling envelope of a SN IIb shows a slower decline rate than SHOOT14di, and the explosion of a red supergiant star with a dense circumstellar wind shows a redder color than SHOOT14di, the shock breakout at the stellar surface of the explosion of a red supergiant star with a small explosion energy of erg reproduces the multicolor light curve of SHOOT14di. This discovery shows that a high-cadence, multicolor optical transient survey at intervals of about one hour, and continuous and immediate follow-up observations, is important for studies of normal core-collapse supernovae at high redshifts.
We estimate the reddening and distance of the nearest starburst galaxy IC 10 using deep near-infrared JHK S photometry obtained with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the ...Subaru telescope. We estimate the foreground reddening toward IC 10 using the UBV photometry of IC 10 from the Local Group Survey, obtaining E(B - V) = 0.52 +/- 0.04 mag. We derive the total reddening including the internal reddening, E(B - V) = 0.98 +/- 0.06 mag, using the UBV photometry of early-type stars in IC 10 and comparing the JHK S photometry of red giant branch stars in IC 10 and the Small Magellanic Cloud. Using the Two Micron All Sky Survey point-source catalog of 20 Galactic globular clusters, we derive a relation between the metallicity Fe/HCG97 and the slope of the red giant branch in the K S - (J - K S) color-magnitude diagram. The mean metallicity of the red giant branch stars in IC 10 is estimated to be Fe/HCG97 = -1.08 +/- 0.28. The magnitude of the tip of the red giant branch (TRGB) of IC 10 in the K S band is measured to be K S,TRGB = 18.28 +/- 0.01. Based on the TRGB method, we estimate the distance modulus of IC 10 to be (m - M)0 = 24.27 +/- 0.03(random) +/- 0.18(systematic), corresponding to the distance of d = 715 +/- 10 +/- 60 kpc. This confirms that IC 10 is a member of the Local Group.
We use the deep wide-field optical imaging data of the Subaru/XMM–Newton Deep Survey to discuss the luminosity- (mass-)dependent galaxy colours down to z′= 25.0 (5 × 109h−270 M⊙) for z∼ 1 galaxies in ...colour-selected high-density regions. We find an apparent absence of galaxies on the red colour–magnitude sequence below z′∼ 24.2, corresponding to ∼M*+ 2 (∼ 1010 M⊙) with respect to passively evolving galaxies at z∼ 1. Galaxies brighter than M*− 0.5 (8 × 1010 M⊙), however, are predominantly red passively evolving systems, with few blue star-forming galaxies at these magnitudes. This apparent age gradient, where massive galaxies are dominated by old stellar populations while less massive galaxies have more extended star formation histories, supports the ‘down-sizing’ idea where the mass of galaxies hosting star formation decreases as the Universe ages. Combined with the lack of evolution in the shape of the stellar mass function for massive galaxies since at least z∼ 1, it appears that galaxy formation processes (both star formation and mass assembly) should have occurred in an accelerated way in massive systems in high-density regions, while these processes should have been slower in smaller systems. This result provides an interesting challenge for modern cold dark matter based galaxy formation theories which predict later formation epochs of massive systems, commonly referred to as ‘bottom-up’.
Subaru Deep Survey I. Near-Infrared Observations Maihara, Toshinori; Iwamuro, Fumihide; Tanabe, Hirohisa ...
Publications of the Astronomical Society of Japan,
02/2001, Letnik:
53, Številka:
1
Journal Article
Recenzirano
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Abstract
Deep near-infrared images of a blank 2$^{\prime}$$ \times$ 2$ ^{\prime}$ section of sky near the galactic north pole taken by Subaru Telescope are presented. The total integration times of ...the $ J$ and $ K^{\prime}$ bands were 12.1 hr and 9.7 hr, resulting in 5$ \sigma$ limiting magnitudes of 25.1 and 23.5 mag, respectively. The numbers of sources within these limiting magnitudes found with an automated detection procedure are 385 in the $ J$ band and 350 in $ K^{\prime}$. Based on photometric measurements of these sources, we present number count vs. magnitude relations, color vs. magnitude diagrams, size vs. color relationships, etc. The slope of the galaxy number count plotted against the AB magnitude scale is about 0.23 in the 22 to 26 AB magnitude range of both bands. The spatial number density of galaxies as well as the slopes in the faint-end region given by the Subaru Deep Field (SDF) survey are consistent with those given by HST-NICMOS surveys, as expressed on the AB magnitude diagram. Several sources having very large $ J - K^{\prime}$ color have been found, including a few $ K^{\prime}$ objects without detection at $ J$. In addition, a number of faint galactic stars were also detected, most of which are assigned to M-subdwarfs, together with a few brown dwarf candidates.
Superwind-Driven Intense H2 Emission in NGC 6240 Ohyama, Youichi; Yoshida, Michitoshi; Takata, Tadafumi ...
Publications of the Astronomical Society of Japan,
08/2000, Letnik:
52, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We have performed a long-slit K-band spectroscopic observation of the luminous infrared galaxy NGC 6240. Spatially extended H2 emission is detected over 3.3 kpc around the two nuclei. The peak ...position of the H2v = 1–0 S(1) emission is located at ∼ 0″.3–0″.4 north of the southern nucleus. Based on line-ratio analyses, we suggest that the excitation mechanism of H2 is pure thermal at most positions. We find the following three velocity components in the H2 emission around the southern nucleus and its south region: a blue-shifted component (≈ –250 km s−1 with respect to Vsys), which is recognized as a distinct C-shape distortion in the velocity field around the southern nucleus; a high-velocity blue-shifted “wing” component (∼ –1000 km s-1 with respect to Vsys); and a component indicating possible line splitting of ∼ 500 km s−1. We show that these kinematic properties can be reproduced by expanding motion of a shell-like structure around the southern nucleus. The offset peak position of the H2 emission can be understood if we assume that the shell expanding to the north interacts with the extragalactic molecular gas which has been transferred during the merging of the two nuclei. At the interface the cloud-crushing mechanism may work efficiently, and shock-excited intense H2 emission is thus expected there. With this mechanism, the H2 luminosity can be explained without global shock driven by the collision of two nuclei. All of these findings lead us to propose a model in which most of the H2 emission is attributed to shock excitation driven by the superwind activity of the southern nucleus.
High-resolution near-infrared J-band imaging with the Subaru Telescope has demonstrated, for the first time from the ground, two independent jets emanating from the protostar L 1551 IRS 5. Successive ...near-infrared spectroscopy has revealed that the jet emission is dominated by FeII lines in the J- and H-bands. While the visual-extinction estimated from the FeII line ratios reaches more than 20 mag in the close vicinity of IRS 5, it decreases rapidly at ∼ 1″ from IRS 5 and remains constant around 7 mag at larger distances. The electron density in the jets is estimated to be 106 cm−3 near IRS 5 and is 104 to 105 cm−3 in their outer section. The twisted appearance of the jets, with bright knots especially prominent in the northern jet, is similar to the R-band jets observed with the Hubble Space Telescope. These results suggest that the twisted structure and bright emission knots are intrinsic to the jets and are not due to a spatial variation of the extinction.
Using the High Dispersion Spectrograph (HDS) at the Subaru Telescope, echelle spectra of two giant arcs, i.e., nebulosities Cw and L associated with HH 131 in Orion are presented. Typical emission ...lines of Herbig-Haro (HH) objects have been detected toward nebulosity Cw with the broadband filter KV 408. With the low-dispersion spectrograph at the National Astronomical Observatories (NAO) 2.16 m telescope, spectra of nebulosities C, L, and K are obtained, which also show strong S II l6717/l6731, Ha, and N II l6583 emission lines. Position-velocity distributions of Cw and L are analyzed from the long-slit spectra observed with the HDS Ha narrowband filter. The fastest radial velocity of Cw is Vr ~ -18.0 km s-1. When the flow at L goes to the south, it slows down. The fastest radial velocity of L has been observed at -45.0 km s-1, and the slowest value is about -18.3 km s-1; the radial velocity gradient is about 200 km s-1 pc-1. The similarity of the fastest radial velocity of Cw to the slowest value of L and their positional connection indicate that they are physically associated. There is a tendency for the entire flow to become less excited and less ionized when going further to the south (i.e., from nebulosities K to L and C), where the most extended (and presumably evolved) objects are seen. The electron densities of all the observed nebulosities are low (ne ~ 102 cm-3). Double-peaked kinematic signatures have been found in Cw from its N II l6583 profiles, while the observed Ha profiles of Cw are almost symmetric. Bow shock models appear to agree with the observed position-velocity diagrams of the N II spectra better than Ha spectra, and a bow shock with its wing, apex, and postshock has been possibly revealed near Cw from the N II emission. With the suggestion that these arcs are HH shocks possibly ejected out of the Orion A molecular cloud by an uncertain source, their spectra show low to intermediate excitation from their diagnostic line ratios.
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