We present a systematic survey of multiple velocity-resolved H 2 O spectra using Herschel/Heterodyne Instrument for the Far Infrared (HIFI) toward nine nearby actively star-forming galaxies. The ground-state and low-excitation lines (E up 130 K) show profiles with emission and absorption blended together, while absorption-free mediumexcitation lines (130 K E up 350 K) typically display line shapes similar to CO. We analyze the HIFI observation together with archival SPIRE/PACS H 2 O data using a state-of-the-art 3D radiative transfer code that includes the interaction between continuum and line emission. The water excitation models are combined with information on the dust and CO spectral line energy distribution to determine the physical structure of the interstellar medium (ISM). We identify two ISM components that are common to all galaxies: a warm10 10 cm 3 ), more extended phase is present. It outputs the emission in the low-excitation H 2 O lines and typically also produces the prominent line absorption features. For the two ULIRGs in our sample (Arp 220 and Mrk 231) an even hotter and more compact (R s 100 pc) region is present, which is possibly linked to AGN activity. We find that collisions dominate the water excitation in the cold gas and for lines with E 300 up K and E 800 up K in the warm and hot component, respectively. Higher-energy levels are mainly excited by IR pumping.
From 1997 to 2006, the Mars Global Surveyor (MGS) spacecraft provided magnetic field measurements while orbiting Mars, extensively sampling the magnetic field at an altitude of about 400 km (Acuña et al., 1998) after periapsis was raised upon completion of the aerobraking phase. The MGS mission discovered that Mars possesses many localized remanent magnetic fields, which most likely originate in the Martian lithosphere (Acuña et al., 1999). Remanent magnetic fields, otherwise known as crustal fields or lithospheric magnetic fields, are widely believed to be induced by an ancient core dynamo. Mars currently does not have a global dipole magnetic field as in the case of Earth and Mercury (Langlais et al., 2010). The most intense crustal fields of Mars are located in the Southern Hemisphere. These fields are 1 to 2 orders of magnitude stronger than the crustal fields on Earth (Kother et al., 2015;Voorhies et al., 2002), 3 to 4 orders of magnitude stronger than the crustal fields on Moon (Purucker & Nicholas, 2010) and Mercury (Johnson et al., 2015).
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