Search

CHIME, the Copernicus Hyperspectral Imaging Mission for the Environment, is one of the six High Priority Candidate Missions (HPCM) of the evolution in the Copernicus Space Component (CSC) foreseen in the mid-2020s that is proposed for further analysis. In this paper we summarize the results as retrieved by OHB (D) as part of the Phase A/B1. The contract was kicked off in 2018 and concluded in 2020 after finalisation of the Pre-development activities. The proposed instrument is a hyperspectral imager instrument with reflective telescope and grating-based spectrometer. The selected orbit is in the range of 625 ± 30 km, LTDN 10:45 – 11:15 am with a repeat cycle of 20 to 25 days for a single satellite and 10-12.5 days revisit for 2 satellites. The payload of each satellite records at a Spatial Sampling Distance (SSD) of 30m the full spectral range from 400 to 2500nm at a Spectral Sampling interval < 10nm with Low Keystone/Smile. On the front end a high performance TMA with wide-band coated optics collects the light from ground and feeds it to a highly linear almost distortion free spectrometer assembly attaining very good spectral stability. All units are integrated in an optical bench structure that offers excellent AIT access and provides a highly stable LOS. The electro-optical backend contains low-noise cold MCT detectors creating margin in the predicted NEDL performance. The instrument can be calibrated via on-board devices or using reference targets outside the spacecraft. We present the functional decomposition and the physical instrument architecture: the optical design and opto-mechanical layout, the electro-optical imaging chain ant thermal control system.

With the development of new spectrometer concepts, it is required to adapt the calibration facilities to characterize correctly their performances. These spectro-imaging performances are mainly Modulation Transfer Function, spectral response, resolution and registration; polarization, straylight and radiometric calibration. The challenge of this calibration development is to achieve better performance than the item under test using mostly standard items. Because only the subsystem spectrometer needs to be calibrated, the calibration facility needs to simulate the geometrical “behaviours” of the imaging system. A trade-off study indicates that no commercial devices are able to fulfil completely all the requirements so that it was necessary to opt for an in home telecentric achromatic design. The proposed concept is based on an Offner design. This allows mainly to use simple spherical mirrors and to cover the spectral range. The spectral range is covered with a monochromator. Because of the large number of parameters to record the calibration facility is fully automatized. The performances of the calibration system have been verified by analysis and experimentally. Results achieved recently on a free-form grating Offner spectrometer demonstrate the capacities of this new calibration facility. In this paper, a full calibration facility is described, developed specifically for a new free-form spectro-imager.

Spectroscopic observations of quasar outflows at rest-frame 500-1000 Angstrom have immense diagnostic power. We present analyses of such data, where absorption troughs from three important ions are measured: first, O IV and O IV* that allow us to obtain the distance of high ionization outflows from the AGN; second, Ne VIII and Mg X that are sensitive to the very high ionization phase of the outflow. Their inferred column densities, combined with those of troughs from O VI, N IV, and H I, yield two important results: 1) The outflow shows two ionization phases, where the high ionization phase carries the bulk of the material. This is similar to the situation seen in x-ray warm absorber studies. Furthermore, the low ionization phase is inferred to have a volume filling factor of 10^(-5)-10^(-6). 2) From the O IV to O IV* column density ratio, and the knowledge of the ionization parameter, we determine a distance of 3000 pc. from the outflow to the central source. Since this is a typical high ionization outflow, we can determine robust values for the mass flux and kinetic luminosity of the outflow: 40 solar masses per year and 10^45 ergs/s, respectively, where the latter is roughly equal to 1% of the bolometric luminosity. Such a large kinetic luminosity and mass flow rate measured in a typical high ionization wind suggests that quasar outflows are a major contributor to AGN feedback mechanisms.

In this paper we analyze the X-ray, UV and optical data of the Seyfert 1.5 galaxy 1H0419-577, with the aim of detecting and studying an ionized-gas outflow. The source was observed simultaneously in the X-rays with XMM and in the UV with HST-COS. Optical data were also acquired with the XMM Optical Monitor. We detected a thin, lowly ionized warm absorber (log xi ~ 0.03, log NH ~19.9 cm^-2) in the X-ray spectrum, consistent to be produced by the same outflow already detected in the UV. Provided the gas density estimated in the UV, the outflow is consistent to be located in the host galaxy, at ~ kpc scale. Narrow emission lines were detected in the X-rays, in the UV and also in the optical spectrum. A single photoionized-gas model cannot account for all the narrow lines emission, indicating that the narrow line region is probably a stratified environment, differing in density and ionization. X-ray lines are unambiguously produced in a more highly ionized gas phase than the one emitting the UV lines. The analysis suggests also that the X-ray emitter may be just a deeper portion of the same gas layer producing the UV lines. Optical lines are probably produced in another, disconnected gas system. The different ionization condition, and the ~ pc scale location suggested by the line width for the narrow lines emitters, argue against a connection between the warm absorber and the narrow line region in this source., 10 pages, 5 figures, accepted for publication in Astronomy and Astrophysics

Active Galactic Nuclei often show evidence of photoionized outflows. A major uncertainty in models for these outflows is the distance ($R$) to the gas from the central black hole. In this paper we use the HST/COS data from a massive multi-wavelength monitoring campaign on the bright Seyfert I galaxy Mrk 509, in combination with archival HST/STIS data, to constrain the location of the various kinematic components of the outflow. We compare the expected response of the photoionized gas to changes in ionizing flux with the changes measured in the data using the following steps: 1) We compare the column densities of each kinematic component measured in the 2001 STIS data with those measured in the 2009 COS data; 2) We use time-dependent photionization calculations with a set of simulated lightcurves to put statistical upper limits on the hydrogen number density that are consistent with the observed small changes in the ionic column densities; 3) From the upper limit on the number density, we calculate a lower limit on the distance to the absorber from the central source via the prior determination of the ionization parameter. Our method offers two improvements on traditional timescale analysis. First, we account for the physical behavior of AGN lightcurves. Second, our analysis accounts for the quality of measurement in cases where no changes are observed in the absorption troughs. The very small variations in trough ionic column densities (mostly consistent with no change) between the 2001 and 2009 epochs allow us to put statistical lower limits on the distance between 100--200 pc for all the major UV absorption components at a confidence level of 99%. These results are mainly consistent with the independent distance estimates derived for the warm absorbers from the simultaneous X-ray spectra., Accepted to A&A (06 APR 2012)

We present analysis of the UV-spectrum of the low-z AGN IRAS-F22456-5125 obtained with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. The spectrum reveals six main kinematic components, spanning a range of velocities of up to 800 km s-1, which for the first time are observed in troughs associated with CII, CIV, NV, SiII, SiIII, SiIV and SIV. We also obtain data on the OVI troughs, which we compare to those available from an earlier FUSE epoch. Column densities measured from these ions allow us to derive a well-constrained photoionization solution for each outflow component. Two of these kinematic components show troughs associated with transitions from excited states of SiII\ and CII. The number density inferred from these troughs, in combination with the deduced ioinization parameter, allows us to determine the distance to these outflow components from the central source. We find these components to be at a distance of ~ 10 kpc. The distances and the number densities derived are consistent with the outflow being part of a galactic wind., 52 pages, 15 figures, accepted for publication in ApJ March 25, 2012

We present medium resolution (R~20,000) HST/COS ultraviolet spectra covering 1155-1760 A of the Seyfert 1 Mrk 509 obtained simultaneously with a Chandra/LETGS spectrum as part of a multiwavelength campaign in 2009 that included observations with XMM-Newton, SWIFT, and Integral. Our high S/N spectrum detects additional complexity in the absorption troughs from a variety of sources in Mrk 509, including the outflow from the active nucleus, the ISM and halo of the host galaxy, and infalling clouds or stripped gas from a merger that are illuminated by the AGN. Variability between the STIS and COS observation of the -400 km/s component allows us to set an upper limit on its distance of < 250 pc. Similarly, variability of a component at +150 km/s between two prior FUSE observations limits its distance to < 1.5 kpc. The UV absorption only partially covers the emission from the AGN nucleus. Covering fractions are lower than those previously seen with STIS, and are comparable to those seen with FUSE. Given the larger apertures of COS and FUSE compared to STIS, we favor scattered light from an extended region near the AGN as the explanation for the partial covering. As observed in prior X-ray and UV spectra, the UV absorption has velocities comparable to the X-ray absorption, but the bulk of the ultraviolet absorption is in a lower ionization state with lower total column density than the gas responsible for the X-ray absorption. We conclude that the outflow from the active nucleus is a multiphase wind., 21 pages, 9 figures. Accepted for publication in Astronomy & Astrophysics, 26 May 2011

We present the most energetic BALQSO outflow measured to date, with a kinetic luminosity of at least 10^46 ergs/s, which is 5% of the bolometric luminosity of this high Eddington ratio quasar. The associated mass flow rate is 400 solar masses per year. Such kinetic luminosity and mass flow rate should provide strong AGN feedback effects. The outflow is located at about 300 pc from the quasar and has a velocity of roughly 8000 km/s. Our distance and energetic measurements are based in large part on the identification and measurement of SIV and SIV* BALs. The use of this high ionization species allows us to generalize the result to the majority of high ionization BALQSOs that are identified by their CIV absorption. We also report the energetics of two other outflows seen in another object using the same technique. The distances of all 3 outflows from the central source (100-2000pc) suggest that we observe BAL troughs much farther away from the central source than the assumed acceleration region of these outflows (0.01-0.1pc)., Comment: Accepted for publication in ApJ, subject of ESO press release: http://www.eso.org/public/news/eso1247

El Pdf del artículo es la versión pre-print: arXiv:1106.2084v1.-- et al., We present absorption line analysis of the outflow in the quasar IRAS F04250–5718. Far-ultraviolet data from the Cosmic Origins Spectrograph on board the Hubble Space Telescope reveal intrinsic narrow absorption lines from high ionization ions (e.g., C IV, N V, and O VI) as well as low ionization ions (e.g., C II and Si III). We identify three kinematic components with central velocities ranging from ~–50 to ~–230 km s–1. Velocity-dependent, non-black saturation is evident from the line profiles of the high ionization ions. From the non-detection of absorption from a metastable level of C II, we are able to determine that the electron number density in the main component of the outflow is 30 cm–3. Photoionization analysis yields an ionization parameter log U H ~ –1.6 ± 0.2, which accounts for changes in the metallicity of the outflow and the shape of the incident spectrum. We also consider solutions with two ionization parameters. If the ionization structure of the outflow is due to photoionization by the active galactic nucleus, we determine that the distance to this component from the central source is 3 kpc. Due to the large distance determined for the main kinematic component, we discuss the possibility that this outflow is part of a galactic wind., We acknowledge support from NASA STScI grants GO 11686 and GO 12022 as well as NSF grant AST 0837880. JIGS and CB acknowledge financial support from the Spanish Ministerio de Ciencia e Innovacion under project AYA2008-06311-C02-02.