| 1. |
- André, Ph., et al.
(författare)
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Probing the cold magnetised Universe with SPICA-POL (B-BOP)
- 2019
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Ingår i: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 36
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Forskningsöversikt (refereegranskat)abstract
- Space Infrared Telescope for Cosmology and Astrophysics (SPICA), the cryogenic infrared space telescope recently pre-selected for a 'Phase A' concept study as one of the three remaining candidates for European Space Agency (ESA's) fifth medium class (M5) mission, is foreseen to include a far-infrared polarimetric imager [SPICA-POL, now called B-fields with BOlometers and Polarizers (B-BOP)], which would offer a unique opportunity to resolve major issues in our understanding of the nearby, cold magnetised Universe. This paper presents an overview of the main science drivers for B-BOP, including high dynamic range polarimetric imaging of the cold interstellar medium (ISM) in both our Milky Way and nearby galaxies. Thanks to a cooled telescope, B-BOP will deliver wide-field 100-350 mu m images of linearly polarised dust emission in Stokes Q and U with a resolution, signal-to-noise ratio, and both intensity and spatial dynamic ranges comparable to those achieved by Herschel images of the cold ISM in total intensity (Stokes I). The B-BOP 200 mu m images will also have a factor similar to 30 higher resolution than Planck polarisation data. This will make B-BOP a unique tool for characterising the statistical properties of the magnetised ISM and probing the role of magnetic fields in the formation and evolution of the interstellar web of dusty molecular filaments giving birth to most stars in our Galaxy. B-BOP will also be a powerful instrument for studying the magnetism of nearby galaxies and testing Galactic dynamo models, constraining the physics of dust grain alignment, informing the problem of the interaction of cosmic rays with molecular clouds, tracing magnetic fields in the inner layers of protoplanetary disks, and monitoring accretion bursts in embedded protostars.
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| 2. |
- Wild, W., et al.
(författare)
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Millimetron—a large Russian-European submillimeter space observatory
- 2009
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:1, s. 221-244
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Tidskriftsartikel (refereegranskat)abstract
- Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution.
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| 3. |
- Gonzalez-Alfonso, E., et al.
(författare)
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HIGH-LYING OH ABSORPTION, [C II] DEFICITS, AND EXTREME LFIR/MH2 RATIOS IN GALAXIES
- 2015
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 800:1, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Herschel/PACS observations of 29 local (ultra) luminous infrared galaxies, including both starburst and active galactic nucleus (AGN) dominated sources as diagnosed in the mid-infrared/optical, show that the equivalent width of the absorbing OH 65 mu m.3/2 J = 9/2-7/2 line (Weq(OH65)) with lower level energy Elow 300 K, is anticorrelated with the [Cii] 158 mu m line to far-infrared luminosity ratio, and correlated with the far-infrared luminosity per unit gas mass and with the 60-to-100 mu m far-infrared color. While all sources are in the active LIR/MH2 > 50L /M mode as derived from previous CO line studies, the OH65 absorption shows a bimodal distribution with a discontinuity at LFIR/MH2 100L /M . In the most buried sources, OH65 probes material partially responsible for the silicate 9.7 mu m absorption. Combined with observations of the OH 71 mu m.1/2 J = 7/2-5/2 doublet (Elow 415 K), radiative transfer models characterized by the equivalent dust temperature, Tdust, and the continuum optical depth at 100 mu m, t100, indicate that strong [C ii] 158 mu m deficits are associated with far-IR thick (t100 0.7, NH 1024 cm-2), warm (Tdust 60 K) structures where the OH 65 mu m absorption is produced, most likely in circumnuclear disks/tori/cocoons. With their high LFIR/MH2 ratios and columns, the presence of these structures is expected to give rise to strong [C ii] deficits. Weq(OH65) probes the fraction of infrared luminosity arising from these compact/warm environments, which is 30%-50% in sources with high Weq(OH65). Sources with high Weq(OH65) have surface densities of both LIR and MH2 higher than inferred from the half-light (CO or UV/optical) radius, tracing coherent structures that represent the most buried/active stage of (circum) nuclear starburst-AGN co-evolution.
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| 4. |
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| 5. |
- Gonzalez-Alfonso, E., et al.
(författare)
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The Mrk 231 molecular outflow as seen in OH
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 561, s. Article no. A27-
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Tidskriftsartikel (refereegranskat)abstract
- We report on the Herschel/PACS observations of OH in Mrk 231, with detections in nine doublets observed within the PACS range, and present radiative-transfer models for the outflowing OH. Clear signatures of outflowing gas are found in up to six OH doublets with different excitation requirements. At least two outflowing components are identified, one with OH radiatively excited, and the other with low excitation, presumably spatially extended and roughly spherical. Particularly prominent, the blue wing of the absorption detected in the in-ladder (2)Pi(3/2) J = 9/2-7/2 OH doublet at 65 mu m, with E-lower = 290 K, indicates that the excited outflowing gas is generated in a compact and warm (circum) nuclear region. Because the excited, outflowing OH gas in Mrk 231 is associated with the warm, far-infrared continuum source, it is most likely more compact (diameter of similar to 200-300 pc) than that probed by CO and HCN. Nevertheless, its mass-outflow rate per unit of solid angle as inferred from OH is similar to that previously derived from CO, greater than or similar to 70 x (2.5 x 10(-6)/X-OH) M-circle dot yr(-1) sr(-1), where X-OH is the OH abundance relative to H nuclei. In spherical symmetry, this would correspond to greater than or similar to 850 x (2.5 x 10(-6)/X-OH) M-circle dot yr(-1), though significant collimation is inferred from the line profiles. The momentum flux of the excited component attains similar to 15 L-AGN/c, with an OH column density of (1.5-3) x 10(17) cm(-2) and a mechanical luminosity of similar to 10(11) L-circle dot. In addition, the detection of very excited, radiatively pumped OH peaking at central velocities indicates the presence of a nuclear reservoir of gas rich in OH, plausibly the 130 pc scale circumnuclear torus previously detected in OH megamaser emission, that may be feeding the outflow. An exceptional (OH)-O-18 enhancement, with OH/(OH)-O-18 less than or similar to 30 at both central and blueshifted velocities, is most likely the result of interstellar-medium processing by recent starburst and supernova activity within the circumnuclear torus or thick disk.
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| 6. |
- Roelfsema, P. R., et al.
(författare)
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SPICA-A Large Cryogenic Infrared Space Telescope : Unveiling the Obscured Universe
- 2018
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Ingår i: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- Measurements in the infrared wavelength domain allow direct assessment of the physical state and energy balance of cool matter in space, enabling the detailed study of the processes that govern the formation and evolution of stars and planetary systems in galaxies over cosmic time. Previous infrared missions revealed a great deal about the obscured Universe, but were hampered by limited sensitivity. SPICA takes the next step in infrared observational capability by combining a large 2.5-meter diameter telescope. cooled to below 8 K, with instruments employing ultra-sensitive detectors. A combination of passive cooling and mechanical coolers will be used to cool both the telescope and the instruments. With mechanical coolers the mission lifetime is not limited by the supply of cryogen. With the combination of low telescope background and instruments with state-of-the-art detectors SPICA provides a huge advance on the capabilities of previous missions. SPICA instruments offer spectral resolving power ranging from R similar to 50 through 11 000 in the 17-230 mu m domain and R similar to 28.000 spectroscopy between 12 and 18 mu m.SPICA will provide efficient 30-37 mu m broad band mapping, and small field spectroscopic and polarimetric imaging at 100, 200 and 350 mu m. SPICA will provide infrared spectroscopy with an unprecedented sensitivity of similar to 5 x 10(-20) W m (-2) (5 sigma/1 h)-over two orders of magnitude improvement over what earlier missions. This exceptional performance leap, will open entirely new domains in infrared astronomy; galaxy evolution and metal production over cosmic time, dust formation and evolution from very early epochs onwards, the formation history of planetary systems.
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