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We obtained a high-resolution VLT-UVES spectrum of the quasar Q2348-011 overa wavelength range that covers most of the prominent metal and molecularabsorption lines from the log N(HI)=20.50+-0.10 damped Lyman-alpha system atzabs=2.43. From the column density ratios and the relative populations of H2rotational and CI fine-structure levels, we derive the physical conditions(relative abundances, dust-depletion, particle density, kinetic temperature andionizing flux) and discuss physical conditions in the neutral phase. Molecularhydrogen is detected in seven components in the first four rotational levels (J= 0-3) of the vibrational ground state. Absorption lines of H2 J = 4 (resp. J =5) are also detected in six (resp. two) of these components. This leads to atotal molecular fraction of log f = -1.69+0.37-0.58. We confirm the earlierfindings that there is a correlation between N(FeII)/N(SII) and N(SiII)/N(SII)indicative of a dust-depletion pattern. Surprisingly, however, the depletion ofmetals onto dust in the H2 components is not large in this system: [Fe/S] =-0.8 to -0.1. The gas in H2-bearing components is found to be cold but stillhotter than similar gas in our Galaxy (T > 130 K, instead of typically 80 K).and dense (n=100-200 cm^-3). There is an anti-correlation between the logarithmof the photo-absorption rate, and log N(H2)/N(CI) derived for each H2component. We show that this is mostly due to shielding effects and impliesthat the photo- absorption rate is a good indicator of the physical conditionsin the gas. We find that the gas is immersed in a intense UV field, about oneorder of magnitude higher than in the solar vicinity. The results suggest thatthe gas in H2-bearing DLAs is clumpy, and star-formation occurs in theassociated object.Comment: 13 pages, 14 figures, accepted for publication in A&

Physical conditions in the neutral interstellar medium at z = 2.43 toward Q 2348-011