Planned NASA space infrared astronomy experiments

A summary is presented of the present status of the NASA space infrared astronomy program. Projects described include the Infrared Astronomy Satellite (IRAS), Small Infrared Telescope on Spacelab 2 (IRT), Cosmic Background Explorer (COBE), Shuttle Infrared Telescope Facility (SIRTF), Space Telescope (ST), and the Large Deployable Reflector (LDR). The important technical developments achieved in these programs are also discussed, as well as critical needs for future missions.     

The Swift GRB MIDEX mission

Swift is a first-of-its-kind multiwavelength transient observatory for γ-ray burst astronomy. It has the optimum capabilities for the next breakthroughs in determining the origin of γ-ray bursts and their afterglows, as well as for using bursts to probe the early Universe. Swift will also monitor the soft gamma repeaters and perform the first sensitive hard X-ray survey of the sky. The mission is being developed by an international collaboration and consists of three instruments, the Burst Alert Telescope (BAT), the X-ray Telescope (XRT), and the Ultraviolet and Optical Telescope (UVOT). The BAT, a wide-field γ-ray detector, will detect >100 γ-ray bursts per year with a sensitivity 5× that of BATSE. The sensitive narrow-field XRT and UVOT will be autonomously slewed to the burst location within 20–70 s to determine 0.3–5.0″ positions and perform optical, UV, and X-ray spectrophotometry. Strong education/public outreach and follow-up programs will help to engage the public and the astronomical community. Swift launch is planned for late 2004.     

Future of Space Astronomy: A global Road Map for the next decades

The use of space techniques continues to play a key role in the advance of astrophysics by providing access to the entire electromagnetic spectrum from radio to high energy γ rays. The increasing size, complexity and cost of large space observatories places a growing emphasis on international collaboration. Furthermore, combining existing and future datasets from space and “ground based” observatories is an emerging mode of powerful and relatively inexpensive research to address problems that can only be tackled by the application of large multi-wavelength observations. While the present set of astronomical facilities is impressive and covers the entire electromagnetic spectrum, with complementary space and “ground based” telescopes, the situation in the next 10–20 years is of critical concern. The James Webb Space Telescope (JWST), to be launched not earlier than 2018, is the only approved future major space astronomy mission. Other major highly recommended space astronomy missions, such as the Wide-field Infrared Survey Telescope (WFIRST), the International X-ray Observatory (IXO), Large Interferometer Space Antenna (LISA) and the Space Infrared Telescope for Cosmology and Astrophysics (SPICA), have yet to be approved for development.     

Sensitivity analysis of test methods for aspheric off-axis mirrors

Following the Hubble Space Telescope (HST), the next generation James Webb Space Telescope (JWST) is being developed to be launched in a few years. JWST will be a segmented mirror telescope with a design much like that developed for ground-based telescopes over the past 20 years. Several segmented mirror telescopes are currently in operation, and next generation ground-based telescopes of the 30-m class are also being designed using segmented primary mirrors. Regardless of size, segmented primary mirror telescopes often require the use of aspheric segment mirrors. One of the key factors in fabrication of aspheric segment mirrors is feasibility of testing off-axis surfaces with high accuracy. A couple of test methods have been investigated for aspheric off-axis segments. As a case study, we apply these test methods to secondary segmented mirror models of the Giant Magellan Telescope. We derive required dimensions of test set-ups and assess sensitivity of optical alignment. Characteristics of the test methods are also discussed.     

Dark Matter searches with GLAST

The Gamma-ray Large Area Space Telescope (GLAST), scheduled to be launched in fall 2007, is the next generation satellite for high-energy gamma-ray astronomy. The Large Area Telescope (LAT), GLAST main instrument, with a wide field of view (>2 sr), a large effective area (>8000 cm² at 1 GeV) and 20 MeV–300 GeV energy range, will provide excellent high energy gamma-ray observations for Dark Matter searches. In this paper we examine the potential of the LAT to detect gamma-rays coming from WIMPS annihilation in the context of supersymmetry. As an example, two search regions are investigated: the galactic center and the galactic satellites.     

Status of the Hubble Space Telescope observatory

The Hubble Space Telescope activity by NASA and ESA began in 1971 and is now nearing completion. The Scientific Instruments are complete and their performance confirmed. The Optical Telescope Assembly integration is proceeding well, with the crucial Fine Guidance Sensors expected to perform as designed. Telescope delivery to the spacecraft contractor is expected in December 1984. Completion of the Verification and Assembly Program will then be followed by launch in the summer of 1986.     

Observed flux density enhancement at submillimeter wavelengths during an X-class flare

We analyse the 30 October, 2004, X1.2/SF solar event that occurred in AR 10691 (N13 W18) at around 11:44 UT. Observations at 212 and 405 GHz of the Solar Submillimeter Telescope (SST), with high time resolution (5 ms), show an intense impulsive burst followed by a long-lasting thermal phase. EUV images from the Extreme Ultraviolet Imaging Telescope (SOHO/EIT) are used to identify the possible emitting sources. Data from the Radio Solar Telescope Network (RSTN) complement our spectral observations below 15 GHz. During the impulsive phase the turnover frequency is above 15.4 GHz. The long-lasting phase is analysed in terms of thermal emission and compared with GOES observations. From the ratio between the two GOES soft X-ray bands, we derive the temperature and emission measure, which is used to estimate the free-free submillimeter flux density. Good temporal agreement is found between the estimated and observed profiles, however the former is larger than the latter.     

High Energy X-ray Telescope Data Analysis Method

The science analysis of the data from the High Energy X-ray Telescope （HE） on the Hard X-ray Modulation Telescope （HXMT） satellite is organized in three stages: calibration, screening and extraction of high-level scientific products. At the first stage, the raw PHA value of each event is converted to PI value accounting for temporal changes in gain and energy offset. At the second stage, the calibrated events are screened by applying cleaning criteria. At the third stage, scientific products, i.e. spectra, light curves and redistribution matrix files, are extracted. This work will introduce the three stages as well as the screening criteria and the data combining method.      

HXMT的空间环境本底计算

硬X射线调制望远镜(HXMT)是一颗宽波段X射线(1～250 keV)天文卫星,其核心载荷高能X射线望远镜(HE)工作于硬X射线能区(20～250 keV),致力于实现硬X射线的高灵敏度巡天观测,描绘硬X射线天图,并对特殊天体作高灵敏度定点观测.为了获得高灵敏度,必须有效地抑制本底.本底主要是由轨道环境中的粒子(γ射线、质子、电子、中子)与探测器相互作用产生的.本文结合大量的描述近地空间本底的文献和最新的实测数据,整理出一套自洽的近地空间本底粒子的数据和公式,便于应用.并通过Geant 4软件模拟计算给出了HXMT的本底及本底随时间和轨道的变化.      

SMESE (SMall Explorer for Solar Eruptions): A microsatellite mission with combined solar payload

The SMESE (SMall Explorer for Solar Eruptions) mission is a microsatellite proposed by France and China. The payload of SMESE consists of three packages: LYOT (a Lyman α imager and a Lyman α coronagraph), DESIR (an Infra-red Telescope working at 35–80 and 100–250 μm), and HEBS (a High Energy Burst Spectrometer working in X- and gamma-rays).     

Roll deconvolution of space telescope data

Roll deconvolution is a speckle method that can improve the resolution of the 2.4m Space Telescope at short UV wavelengths. In digital simulations we have investigated the dependence of the signal-to-noise ratio of the reconstruction on photon noise (10⁴ to 10 photons per pixel), the object size, the telescope point spread function and guiding errors.     

SMESE: A SMall Explorer for Solar Eruptions

The SMall Explorer for Solar Eruptions (SMESE) mission is a microsatellite proposed by France and China. The payload of SMESE consists of three packages: LYOT (a Lyman imager and a Lyman coronagraph), DESIR (an Infra-Red Telescope working at 35–80 and 100–250 μm), and HEBS (a High-Energy Burst Spectrometer working in X- and γ-rays).

The status of research on flares and coronal mass ejections is briefly reviewed in the context of on-going missions such as SOHO, TRACE and RHESSI. The scientific objectives and the profile of the mission are described. With a launch around 2012–2013, SMESE will provide a unique tool for detecting and understanding eruptions (flares and coronal mass ejections) close to the maximum phase of activity.     

Status of the Hard X-ray Modulation Telescope (Insight-HXMT) Project

The Hard X-ray Modulation Telescope (HXMT) was launched at Jiuquan Satellite Launch Center on June 15, 2017, and was named as Insight-HXMT after the launch. Now all the instruments work properly in space, dozens of sources have been observed, and some early scientific results have been published. The nominal lifetime of Insight-HXMT is 4 years.      

Forbush decreases and solar events seen in the 10–20 GeV energy range by the Karlsruhe Muon Telescope

Since 1993, a muon telescope located at Forschungszentrum Karlsruhe (Karlsruhe Muon Telescope) has been recording the flux of single muons mostly originating from primary cosmic-ray protons with dominant energies in the 10–20 GeV range. The data are used to investigate the influence of solar effects on the flux of cosmic rays measured at Earth. Non-periodic events like Forbush decreases and ground level enhancements are detected in the registered muon flux. A selection of recent events will be presented and compared to data from the Jungfraujoch neutron monitor. The data of the Karlsruhe Muon Telescope help to extend the knowledge about Forbush decreases and ground level enhancements to energies beyond the neutron monitor regime.     

The occurrence of single hard X-raysources in solar flares

The ‘standard’ thick target flare model predicts the existence of strong hard X-ray emission at the footpointsof a flare loop. However, Yohkoh observations suggest that up to 20% of events with data available in three or more Hard X-ray Telescope (HXT) channels show only a single source. Combining datasets from Yohkoh, the Solar and Heliospheric Observatory (SOHO), and Nobeyama Radio Heliograph (NoRH), we compare the characteristics of these single source events to double source events. The objective of this study is to determine whether these represent unresolved double footpoints, asymmetric electron deposition due to magnetic mirroring effects, or a genuine departure from the ‘standard’ model.     

Star visibility and tracking from the Space Station

Purpose of the present study is to provide algorithms for and examples of how to simulate star visibility and tracking by a Telescope attached to the main truss of the International Space Station (ISS).     

Results from the Far Ultraviolet Space Telescope (FAUST)

We present early results from the Far Ultraviolet Space Telescope (FAUST), which flew in March 1992 with the ATLAS space shuttle mission. The telescope provides wide-field images in the far ultraviolet (1400–1800 Å). Studies underway using the data obtained on this mission include establishing the brightness and distribution of far ultraviolet stars in the halo of our Galaxy, establishing the far ultraviolet properties of nearby galaxies and nearby clusters of galaxies, analyzing the diffuse galactic light, and searching for the origin of the extragalactic ultraviolet light. We discuss the instrument performance, and early results from these observations.     

Collimator-based Fourier-transform imaging

In viewpoint of signal processing, we describe the principle of collimator-based Fourier-transform imaging, from verifying Fourier-transform function of collimator to presenting theoretical model of dirty image. This gives us a guideline in designing collimator imager, that is configuring the subcollimators properly to improve the quality of the dirty image. Here we optimize the arrangement of the subcollimators of YOHKOH Hard X-ray Telescope (HXT) to get the Point Spread Function of sidelobes as small as possible and simulate that with MATLAB.     

Space Telescope Science operations

The activities which will take place at the Space Telescope Science Institute (ST Sci) in support of science operations will be summarized. These activities follow proposal acceptance and range over planning and scheduling, observation implementation, data processing and archiving, and support of astronomers in all these.     

Goddard Robotic Telescope – Optical follow-up of GRBs and coordinated observations of AGNs

Since it is not possible to predict when a Gamma-Ray Burst (GRB) will occur or when Active Galactic Nucleus (AGN) flaring activity starts, follow-up/monitoring ground telescopes must be located as uniformly as possible all over the world in order to collect data simultaneously with Fermi and Swift detections. However, there is a distinct gap in follow-up coverage of telescopes in the eastern U.S. region based on the operations of Swift. Motivated by this fact, we have constructed a 14″ fully automated optical robotic telescope, Goddard Robotic Telescope (GRT), at the Goddard Geophysical and Astronomical Observatory. The aims of our robotic telescope are (1) to follow-up Swift/Fermi GRBs and (2) to perform the coordinated optical observations of Fermi Large Area Telescope (LAT) AGN. Our telescope system consists of off-the-shelf hardware. With the focal reducer, we are able to match the field of view of Swift narrow instruments (20′ × 20′). We started scientific observations in mid-November 2008 and GRT has been fully remotely operated since August 2009. The 3σ upper limit in a 30 s exposure in the R filter is ∼15.4 mag; however, we can reach to ∼18 mag in a 600 s exposures. Due to the weather condition at the telescope site, our observing efficiency is 30–40% on average.