The Statistical and Physical Properties of the Low‐Redshift Lyα Forest Observed with theHubble Space Telescope/STIS

AbstractGravitational lensing from galaxy clusters has great potential for deriving the prevalence and physical properties of ultra-faint galaxies at early times, with recent very impressive results from the Hubble Frontier Fields program. Important issues in deriving the most accurate results are accurate constraints on source sizes and a robust treatment of uncertainties in the magnification models. Using > 3300 z = 2 – 10 galaxies behind the 6 Hubble Frontier Fields clusters and a forwards modeling approach, I describe the efforts of my collaborators and me to map out the galaxy luminosity functions at ∼ − 13 mag from z ∼ 9 to z ∼ 2, i.e, a factor of 1000 below Lå and to the typical luminosity of galaxies suspected to drive cosmic reionization. Additionally, I discuss the constraints we can obtain on the properties of faint sources, in particular their stellar masses, mass-to-light ratios, colors, and stellar population ages. I conclude with a prospective on using cluster lenses to study the distant universe with the James Webb Space Telescope.

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The distribution and physical properties of high-redshift [Oiii] emitters in a cosmological hydrodynamics simulation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319002424 ◽

2019 ◽

Vol 15 (S341) ◽

pp. 249-252

Author(s):

Kana Moriwaki

Keyword(s):

Physical Properties ◽

Physical Model ◽

High Redshift ◽

Gas Density ◽

Space Telescope ◽

James Webb Space Telescope ◽

Local Relation

AbstractAtacama Large Millimeter/submillimeter Array (ALMA) has enabled us to detect [Oiii] 88 μm line even at z > 9. To study the properties of high-redshift [Oiii] emitters, we calculate [Oiii] luminosities of galaxies in a cosmological simulation by applying a physical model of Hii region and using the photoionization code cloudy. We find that the [Oiii] 88 μm luminosity, LOIII,88, scales with SFR with slightly larger LOIII,88 than a local relation. Some [Oiii] emitters have extended disk-like structure. We propose to use the ratio between [Oiii] 88 μm line and [Oiii] 5007 Å line, which can be detected with James Webb Space Telescope (JWST), to estimate the gas density and the metallicity in HII region of high-redshift [Oiii] emitters.

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The R136 star cluster dissected with Hubble Space Telescope/STIS – II. Physical properties of the most massive stars in R136

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2801 ◽

2020 ◽

Vol 499 (2) ◽

pp. 1918-1936 ◽

Cited By ~ 2

Author(s):

Joachim M Bestenlehner ◽

Paul A Crowther ◽

Saida M Caballero-Nieves ◽

Fabian R N Schneider ◽

Sergio Simón-Díaz ◽

...

Keyword(s):

Physical Properties ◽

Hubble Space Telescope ◽

Massive Stars ◽

Mass Function ◽

Large Magellanic Cloud ◽

Spectroscopic Studies ◽

Initial Mass Function ◽

Space Telescope ◽

Power Law Exponent ◽

Red Supergiants

ABSTRACT We present an optical analysis of 55 members of R136, the central cluster in the Tarantula Nebula of the Large Magellanic Cloud. Our sample was observed with STIS aboard the Hubble Space Telescope, is complete down to about 40 M⊙, and includes seven very massive stars with masses over 100 M⊙. We performed a spectroscopic analysis to derive their physical properties. Using evolutionary models, we find that the initial mass function of massive stars in R136 is suggestive of being top-heavy with a power-law exponent γ ≈ 2 ± 0.3, but steeper exponents cannot be excluded. The age of R136 lies between 1 and 2 Myr with a median age of around 1.6 Myr. Stars more luminous than log L/L⊙ = 6.3 are helium enriched and their evolution is dominated by mass-loss, but rotational mixing or some other form of mixing could be still required to explain the helium composition at the surface. Stars more massive than 40 M⊙ have larger spectroscopic than evolutionary masses. The slope of the wind–luminosity relation assuming unclumped stellar winds is 2.41 ± 0.13 which is steeper than usually obtained (∼1.8). The ionizing ($\log Q_0\, [{\rm ph/s}] = 51.4$) and mechanical ($\log L_{\rm SW}\, [{\rm erg/s}] = 39.1$) output of R136 is dominated by the most massive stars ($\gt 100\, \mathrm{ M}_{\odot }$). R136 contributes around a quarter of the ionizing flux and around a fifth of the mechanical feedback to the overall budget of the Tarantula Nebula. For a census of massive stars of the Tarantula Nebula region, we combined our results with the VLT-FLAMES Tarantula Survey plus other spectroscopic studies. We observe a lack of evolved Wolf–Rayet stars and luminous blue and red supergiants.

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HST observations of [O III] emission in nearby QSO2s: Physical properties of the outflows

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320004196 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 269-271

Author(s):

Anna Trindade Falcao ◽

S. B. Kraemer ◽

T. C. Fischer ◽

D. M. Crenshaw ◽

M. Revalski ◽

...

Keyword(s):

Physical Properties ◽

Emission Line ◽

Radial Distance ◽

Space Telescope ◽

X Ray ◽

Medium Resolution ◽

Mass Outflow ◽

Imaging Spectrograph

AbstractWe used Space Telescope Imaging Spectrograph (STIS) long slit medium-resolution G430M and G750M spectra to analyze the extended [O III] λ5007 emission in a sample of twelve QSO2s from Reyes et al. (2008). The purpose of the study was to determine the properties of the mass outflows and their role in AGN feedback. We measured fluxes and velocities as functions of deprojected radial distances. Using photoionization models and ionizing luminosities derived from [O III], we were able to estimate the densities for the emission-line gas. From these results, we derived masses, mass outflow rates, kinetic energies and kinetic luminosity rates as a function of radial distance for each of the targets. Masses are several times 103 - 107 solar masses, which are comparable to values determined from a recent photoionization study of Mrk 34 (Revalski). Additionally, we are studying the possible role of X-ray winds in these QSO2s.

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Spitzer Space Telescope observations of bilobate comet 8P/Tuttle

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936458 ◽

2019 ◽

Vol 632 ◽

pp. A104

Author(s):

O. Groussin ◽

P. L. Lamy ◽

M. S. P. Kelley ◽

I. Toth ◽

L. Jorda ◽

...

Keyword(s):

Physical Properties ◽

Confidence Level ◽

Thermal Inertia ◽

Infrared Camera ◽

Equilibrium Temperature ◽

Space Telescope ◽

Nucleus Shape ◽

Independent Observations ◽

Dust Grain ◽

Pole Orientation

Context. Comet 8P/Tuttle is a nearly isotropic comet whose physical properties are poorly known and might be different from those of ecliptic comets owing to their different origin. Two independent observations have shown that 8P/Tuttle has a bilobate nucleus. Aims. Our goal is to determine the physical properties of the nucleus (size, shape, thermal inertia, and albedo) and coma (water and dust) of 8P/Tuttle. Methods. We observed the inner coma of 8P/Tuttle with the infrared spectrograph and the infrared camera of the Spitzer Space Telescope. We obtained one spectrum (5–40 μm) on 2 November 2007 and a set of 19 images at 24 μm on 22–23 June 2008 sampling the rotational period of the nucleus. The data were interpreted using thermal models for the nucleus and the dust coma, and we considered two possible shape models of the nucleus derived from Hubble Space Telescope visible and Arecibo radar observations. Results. We favor a model for the nucleus shape that is composed of two contact spheres with respective radii of 2.7 ± 0.1 km and 1.1 ± 0.1 km and a pole orientation with RA = 285 ± 12° and Dec = +20 ± 5°. The thermal inertia of the nucleus lies in the range 0–100 J K−1 m−2 s−1∕2 and the R-band geometric albedo is 0.042 ± 0.008. The water production rate amounts to 1.1 ± 0.2 × 1028 molecules s−1 at 1.6 AU from the Sun pre-perihelion, which corresponds to an active fraction of ≈9%. At the same distance, the ɛfρ quantity amounts to 310 ± 34 cm, and it reaches 325 ± 36 cm at 2.2 AU post-perihelion. The dust grain temperature is estimated to be 258 ± 10 K, which is 37 K higher than the thermal equilibrium temperature at 1.6 AU. This indicates that the dust grains that contribute to the thermal infrared flux have a typical size of ≈10 μm. The dust spectrum exhibits broad emission around 10 μm (1.5σ confidence level) and 18 μm (5σ confidence level) that we attribute to amorphous pyroxene.

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Hubble Space Telescope Observations of [O III] Emission in Nearby QSO2s: Physical Properties of the Ionised Outflows

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3239 ◽

2020 ◽

Author(s):

Anna Trindade Falcão ◽

S B Kraemer ◽

T C Fischer ◽

D M Crenshaw ◽

M Revalski ◽

...

Keyword(s):

Physical Properties ◽

Emission Line ◽

Hubble Space Telescope ◽

Radial Distance ◽

Flow Rates ◽

Space Telescope ◽

Bolometric Luminosity ◽

Mass Outflow ◽

Peak Outflow ◽

Imaging Spectrograph

Abstract We use Hubble Space Telescope (HST)/ Space Telescope Imaging Spectrograph (STIS) long-slit G430M and G750M spectra to analyse the extended [O III] λ5007 emission in a sample of twelve nearby (z >0.12) luminous (Lbol > 1.6 × 1045 erg s−1) QSO2s. The purpose of the study is to determine the properties of the mass outflows of ionised gas and their role in AGN feedback. We measure fluxes and velocities as functions of radial distances. Using Cloudy models and ionising luminosities derived from [O III] λ5007, we are able to estimate the densities for the emission-line gas. From these results, we derive masses of [O III]-emitting gas, mass outflow rates, kinetic energies, kinetic luminosities, momenta and momentum flow rates as a function of radial distance for each of the targets. For the sample, masses are several times 103M⊙ − 107M⊙ and peak outflow rates are 9.3 × 10−3M⊙ yr−1 to 10.3 M⊙ yr−1. The peak kinetic luminosities are 3.4 × 10−8 to 4.9 × 10−4 of the bolometric luminosity, which does not approach the 5.0 × 10−3 - 5.0 × 10−2 range required by some models for efficient feedback. For Mrk 34, which has the largest kinetic luminosity of our sample, in order to produce efficient feedback there would have to be 10 times more [O III]-emitting gas than we detected at its position of maximum kinetic luminosity. Three targets show extended [O III] emission, but compact outflow regions. This may be due to different mass profiles or different evolutionary histories.

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Introduction to the Solar Space Telescope

International Astronomical Union Colloquium ◽

10.1017/s025292110006437x ◽

2000 ◽

Vol 179 ◽

pp. 141-147

Author(s):

G. Ai ◽

S. Jin ◽

S. Wang ◽

B. Ye ◽

S. Yang

Keyword(s):

Solar Telescope ◽

Basic Aspect ◽

Space Telescope ◽

Space Solar Telescope

AbstractThe design of the space solar telescope (SST) (phase B) has been completed. The manufacturing is under development. At the end of 2000, it will be assembled. The basic aspect will be introduced in this paper.

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The Photometric Properties of the Ap Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100080684 ◽

1976 ◽

Vol 32 ◽

pp. 365-377 ◽

Cited By ~ 2

Author(s):

B. Hauck

Keyword(s):

Physical Properties ◽

Ap Stars

The Ap stars are numerous - the photometric systems tool It would be very tedious to review in detail all that which is in the literature concerning the photometry of the Ap stars. In my opinion it is necessary to examine the problem of the photometric properties of the Ap stars by considering first of all the possibility of deriving some physical properties for the Ap stars, or of detecting new ones. My talk today is prepared in this spirit. The classification by means of photoelectric photometric systems is at the present time very well established for many systems, such as UBV, uvbyβ, Vilnius, Geneva and DDO systems. Details and methods of classification can be found in Golay (1974) or in the proceedings of the Albany Colloquium edited by Philip and Hayes (1975).

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The Infection of Cells by Bullet-Shaped Viruses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063779 ◽

1969 ◽

Vol 27 ◽

pp. 372-373

Author(s):

Frederick A. Murphy ◽

Alyne K. Harrison ◽

Sylvia G. Whitfield

Keyword(s):

Electron Microscopy ◽

Physical Properties ◽

Host Cell ◽

Thin Section ◽

Cultured Cells ◽

Cell Infection ◽

Thin Section Electron Microscopy ◽

Section Electron ◽

Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

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