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We present deep, high velocity resolution (~1.6 km/s) Giant Meterwave Radio Telescope HI 21cm synthesis images for the faint (M_B ~ -12.1) dwarf irregular galaxy GR8. We find that the velocity field of the galaxy shows a clear systematic large scale pattern, with a maximum amplitude ~10 km/s. Neither pure rotation, nor pure radial motion alone can fit the observed velocity field; however a combination of radial and circular motions can provide a reasonable fit. The most natural interpretation is that the neutral ISM, in addition to rotating about the center, is also expanding outwards, as a result of energy input from the ongoing star formation in the galaxy. Support for this interpretation comes from the fact that the pressure in the HII regions in the galaxy is known to be substantially (~55 times) more than the average pressure in the gas disk. It is, however, also possible that the velocity field is the result of the gas swirling inwards, in which case GR8 could be in the process of formation via the merger of subgalactic clumps., Comment: 9 pages, 5 figures. Accepted for publication in Astronomy and astrophysics

We present the results of deep, high velocity resolution (~1.6 km/s) Giant Meterwave Radio Telescope (GMRT) HI 21cm observations of extremely faint (M_B > -12.5) dwarf irregular galaxies. We find that all of our sample galaxies show systematic large scale velocity gradients, unlike earlier studies which found chaotic velocity fields for such faint galaxies. For some of the sample galaxies the velocity fields are completely consistent with ordered rotation, though the peak circular velocities are comparable to the observed random motions. These are the faintest known galaxies with such regular kinematics. We present ("asymmetric drift" corrected) rotation curves and mass models (including fits for Isothermal and NFW halos) for some of these galaxies and discuss the implications for hierarchical models of galaxy formation., Comment: 6 pages, 5 figures. To appear in the proceedings for IAU Symp. 220 "Dark Matter in Galaxies", ASP, Eds: S. Ryder, D.J. Pisano, M. Walker, K.C. Freeman

We present deep, high velocity resolution (~1.6 km/s) Giant Meterwave Radio Telescope (GMRT) HI 21cm synthesis images of the faint (M_B ~ -10.6) local group dwarf galaxy DDO210. We find that the HI distribution in the galaxy is not axi-symmetric, but shows density enhancements in the eastern and southern halves of the galaxy. The optical emission is lopsided with respect to the HI, most of the bright optical emission arises from the eastern half of the HI disk. The velocity field of the galaxy is however quite regular and shows a systematic large scale pattern, consistent with the rotational motion. The rotation curve for the galaxy shows a peak (inclination corrected) rotation velocity of only ~8 km/s, comparable to the random motions in the HI gas. After correcting for the dynamical support provided by random motions (the ``asymmetric drift'' correction), we find the corrected peak rotation velocity of ~16.0 km/s. Mass modeling of the corrected rotation curve shows that the kinematics of DDO210 can be well fit with either a modified isothermal halo (with a central density rho_0 ~ 29 X 10^{-3} M_\odot pc^{-3} for a stellar mass to light ratio of 3.4) or an NFW halo. In the case of the NFW halo however, a good fit is obtained for a wide range of parameters; the halo parameters could not be uniquely determined from the fit. Density profiles with inner slope steeper than ~1.2 however provide a poor fit to the data. Finally, the rotation curve derived using MOND also provides a reasonable fit to the observed rotation curve., Comment: 11 pages, 12 figures. Accepted for publication in Astronomy & Astrophysic

We present Giant Meterwave Radio Telescope images of the 1065 MHz emission from the 1_11 -> 1_10 rotational transition of acetaldehyde (CH3CHO) in the molecular cloud complex Sgr B2. Our observations are unique in that they have a high spatial resolution (~4"), while still being sensitive to large-scale emission. Most complex organic molecules in this cloud (e.g. acetone, methyl formate, acetic acid) are concentrated in a very small core, ~0.1pc across. In contrast, acetaldehyde is found to be spread over a region at least 100 times larger in extent. The line emission is confined to regions with radio continuum emission and correlates well (in both position and velocity) with formaldehyde absorption towards this continuum; this is consistent with earlier single dish results suggesting that it is likely to be weakly mased. Our observations also suggest that grain mantle destruction by shocks plays an important role in the observed gas phase abundance of CH3CHO in Sgr B2., Comment: accepted for publication in A&A (letters)

We present deep, high velocity resolution (1.6 km/s) GMRT HI as well as optical data for the faint (M_B ~ -10.9) galaxy Camelopardalis B. We find that the HI in the galaxy has a regular velocity field, consistent with rotational motion. The implied kinematical major axis is well aligned with the major axis of both the HI and optical images. Cam B is the faintest known galaxy with such relatively well behaved kinematics. From the HI velocity field we derive a rotation curve for the galaxy. The peak (inclination corrected) rotation velocity is only 7km/s, comparable to the observed velocity dispersion. After correcting the observed rotation velocities for random motions (the "asymmetric drift" correction) we find a corrected peak rotation velocity of ~ 20 km/s. On fitting mass models to corrected rotation curve we find that the kinematics of Cam B is well fit with a modified isothermal halo with central density $\rho_0$ approximately 12.0 $M_\odot$ pc$ ^{-3}$. This derived central density has only a very weak dependence on the assumed M/L ratio of the stellar disk. We also find that the corrected rotation curve cannot be fit with an NFW halo regardless of the assumed M/L ratio. We compile from the literature a sample of galaxies with rotation curves obtained from HI synthesis observations. From this sample (which has an absolute magnitude range of ~ 12) we find (i) that Cam B lies on the Tully-Fisher relation defined by these galaxies, provided we use the corrected rotation velocity, and (ii) a weak trend for increasing halo central density with decreasing galaxy size. Such a trend is expected in hierarchical models of halo formation., Comment: Accepted for publication in New Astronomy. For copyright reasons this version is slightly different from the accepted version, although the differences are minor

We present deep GMRT 21cm absorption spectra of 10 damped Lyman-$\alpha$ systems (DLAs), of which 8 are at redshifts $z \ga 1.3$. HI absorption was detected in only one DLA, the $z = 0.5318$ absorber toward PKS 1629+12, which has been identified with a luminous spiral galaxy; the spin temperature limit ($T_s \le 310$ K) derived from our observations continues the trend of DLAs associated with bright spirals having low spin temperatures. In 7 of the remaining 9 systems, the observations place strong lower limits on the spin temperature of the HI gas. The sample of DLAs searched for 21cm absorption now consists of 31 systems, with $T_s$ estimates available in 24 cases; of these, 16 are at $z < 2$ and 8 at $z > 2$, with 11 (all at $z < 1$) having optical IDs. For the latter 11 systems, we find that all low $T_s$ DLAs have been identified with luminous galaxies, while all high $T_s$ ($T_s \ga 1000$ K) DLAs have been identified with either LSBs or dwarfs. DLA spin temperatures thus appear to correlate with galaxy type, with no correlation seen between $T_s$ and impact parameter. The trend that low $z$ DLAs exhibit both high and low $T_s$ values while high redshift ($z \ga 3$) DLAs only show high spin temperatures is present in this expanded data set. Based on this difference in spin temperatures, the Gehan test rules out the hypothesis that DLAs at $z > 2$ and DLAs at $z < 2$ are drawn from the same parent population at ~ 99 % confidence level. Finally, we estimate upper limits on the fraction of cold HI, $f_{CNM}$, in the $z \ga 3$ DLAs. In local spirals, $f_{CNM} \sim 0.5$; in contrast, we find that $f_{CNM} < 0.3$ in all 7 high $z$ DLAs, with $f_{CNM} < 0.1$ in 5 of the 7 cases. (abridged), Comment: 13 pages, 5 figures. Accepted for publication in Astronomy & Astrophysics

We present Giant Metrewave Radio Telescope (GMRT) HI 21cm emission images of the z=0.009 damped Lyman-alpha (DLA) absorber towards the QSO HS 1543+5921. The DLA has been earlier identified as a low surface brightness galaxy SBS 1543+593 at an impact parameter of ~ 400 pc to the QSO line of sight. The extremely low redshift of the absorber allows us to make spatially resolved images of the 21cm emission; besides the HI mass, this also enables us to determine the velocity field of the galaxy and, hence, to estimate its dynamical mass. We obtain a total HI mass of ~ 1.4x10^9 Msun, considerably smaller than the value of M*(HI) determined from blind 21cm emission surveys. This continues the trend of low HI mass in all low redshift DLAs for which HI emission observations have been attempted. We also find that the QSO lies behind a region of low local HI column density in the foreground galaxy. This is interesting in view of suggestions that DLA samples are biased against high HI column density systems. The dynamical mass of the galaxy is found to be Mdyn ~ 5x10^9 Msun., Comment: Accepted for publication in A&A

We present Giant Metrewave Radio Telescope (GMRT) observations of redshifted 21-cm absorption from the $z=0.437$ metal line absorption system towards PKS 1243-072. HI absorption is clearly detected; the absorption profile has a velocity spread of $\sim 20$ km/s. Detection of 21-cm absorption indicates that the absorber has an HI column density large enough to be classified as a damped Lyman-$\alpha$ system. Follow up ground based optical imaging and spectroscopy allow us to identify the absorber with an $L \sim L^\star$ galaxy at an impact parameter of $\sim 9.8$ kpc from the line of sight to the QSO. The absorbing galaxy is unusual in that it has bright emission lines. On the basis of the optical spectrum we are unable to uniquely classify the galaxy since its emission line ratios lie in the transition region between starburst and Seyfert II type spectra., Comment: 5 pages, 3 figures. Accepted for publication in Astronomy & Astrophysics

We present Giant Metrewave Radio Telescope (GMRT) observations of OH absorption in B3~1504+377 ($z \sim 0.673$) and PKS 1413+135 ($z \sim 0.247$). OH has now been detected in absorption towards four intermediate redshift systems, viz. the lensing galaxies towards B~0218+357 ($z \sim 0.685$; Kanekar et al. 2001) and 1830-211 ($z \sim 0.886$; Chengalur et al. 1999), in addition to the two systems listed above. All four systems also give rise to well studied millimetre wavelength molecular line absorption from a host of molecules, including HCO$^+$. Comparing our OH data with these millimetre line transitions, we find that the linear correlation between $N_{\rm OH}$ and $N_{\rm HCO^+}$ found in molecular clouds in the Milky Way (Liszt & Lucas 1996) persists out to $z \sim 1$. It has been suggested (Liszt & Lucas 1999) that OH is a good tracer of ${\rm H_2}$, with $N_{\rm H_2}/N_{\rm OH} \approx 10^7$ under a variety of physical conditions. We use this relationship to estimate $N_{\rm H_2}$ in these absorbers. The estimated $N_{\rm H_2}$ is $\ga 10^{22}$ in all four cases and substantially different from estimates based on CO observations., Comment: 4 pages, 3 figures. Accepted for publication in Astronomy and Astrophysics Letters

We discuss Australia Telescope Compact Array (ATCA) HI 21cm data for the galaxy cluster A3128. Our observations are intentionally relatively shallow, and a blind search through our data cube yields (tentative) detections of only two galaxies, of which one is probably spurious. A3128 is part of the ESO Nearby Abell Cluster Survey (ENACS); redshifts are available for 193 galaxies in the A3128 region. For 148 of these galaxies the redshifts are such that the HI emission (if any) would lie within our data cube. We use the known redshifts of these galaxies to coadd their spectra and thus improve our sensitivity to HI emission. The technique is fairly successful -- the coadded spectra allow detection of an average mass content of ~ 9x10^8 Msun, almost an order of magnitude lower than for direct detection of individual objects. By dividing the total galaxy sample into subsamples we find that the gas content of late type galaxies that lie outside the X-ray emitting core of the cluster is substantially higher than that of those within the core. Even outside the X-ray emitting region the distribution of gas-rich galaxies in the cluster is not uniform, we find that gas-rich galaxies are concentrated in the east of the cluster. This is consistent with earlier analyses of the kinematics of the galaxies in A3128 which indicate the presence of subclustering. In summary we find that coadding spectra is a powerful tool for the study of HI in cluster galaxies, and suggest that this technique could be applied to substantially increase the redshift range over which such observations could be carried out., Comment: 8pages, 7 figures accepted for publication in A&A

We present sensitive Giant Metrewave Radio Telescope (GMRT) and high-resolution Arecibo HI 21-cm observations of the damped Lyman-$\alpha$ absorber (DLA) at $z=0.2212$ towards OI 363. The spectra are in excellent agreement and yield a spin temperature $T_s = 890 \pm 160$ K, far higher than $T_s$ values measured in local spirals, but similar to values obtained in the majority of DLAs ($T_s \ga 1000$ K). The high velocity resolution of the Arecibo spectra enables us to obtain estimates of physical conditions in the absorbing clouds by fitting multiple Gaussians to the absorption profile. The spectra are well fit by a three-component model with two narrow and one wide components, with temperatures ${T_{k_1}} = 308 \pm 24$ K, ${T_{k_2}} = 180 \pm 30$ K and ${T_{k_3}} = 7600 \pm 1250$ K, respectively. The last of these is in excellent agreement with the expected temperatures for the WNM ($5000 - 8000$ K). The mere fact that components are seen with lower temperatures than the estimated $T_s$ implies that the absorber must have a multi-phase medium. We use the measured 21-cm optical depth and the above estimates of the kinetic temperature to obtain the HI column density in the various components. The total column density in the narrow components is found to be $\NHI (CNM) \le 1.9 \pm 0.25 \times 10^{20}$ cm, while that in the wide component is $\NHI (WNM) \ge 1.26 \pm 0.49 \times 10^{21}$ cm. Thus, the WNM contains at least 75% of the total HI in the $z = 0.2212$ DLA, unlike our Galaxy, in which the CNM and WNM have equitable contributions; this accounts for the difference in the spin temperatures of the $z = 0.2212$ system and local spirals, suggesting that the DLA is probably a dwarf or LSB type galaxy (abridged)., Comment: 8 pages, 2 figures. Accepted for publication in Astronomy and Astrophysics. Minor typos removed

Nearby interstellar clouds with high (|v| >/= 10 km/s) random velocities although easily detected in NaI and CaII lines have hitherto not been detected (in emission or absorption) in the HI 21cm line. We describe here deep Giant Metrewave Radio Telescope (GMRT) HI absorption observations toward radio sources with small angular separation from bright O and B stars whose spectra reveal the presence of intervening high random velocity CaII absorbing clouds. In 5 out of the 14 directions searched we detect HI 21cm absorption features from these clouds. The mean optical depth of these detections is ~ 0.09 and FWHM is ~ 10 km/s, consistent with absorption arising from CNM clouds., Comment: 16 pages, 6 figures (included), Accepted for publication in Journal of Astrophysics & Astronomy, uses jaa.sty

We report multi-epoch GMRT HI observations of the z = 0.3127 damped absorber towards the quasar PKS 1127-145, which reveal variability in both the absorption profile and the flux of the background source, over a time-scale of a few days. The observed variations cannot be explained by simple inter-stellar scintillation (ISS) models where there are only one or two scintillating components and all of the ISS occurs in the Galaxy. More complicated models where there are either more scintillating components or some of the ISS occurs in the ISM of the z=0.3127 absorber may be acceptable. However, the variability can probably best be explained in models incorporating motion (on sub-VLBI scales) of a component of the background continuum source, with or without some ISS. All models for producing the variable 21cm absorption profile require small scale variations in the 21cm optical depth of the absorber. The length scale for the opacity variations is $\sim 0.1$ pc in pure super-luminal motion models, and $\sim$ 10 pc in pure ISS models. Models involving sub-luminal motion, combined with scintillation of the moving component, require opacity variations on far smaller scales, $\sim$ 10 - 100 AU., Comment: 5 pages, 2 figures. Accepted for publication in MNRAS

We report Giant Metrewave Radio Telescope (GMRT) 21cm observations of two confirmed and one candidate low redshift damped Lyman-alpha systems (DLAS). HI absorption was detected in the two confirmed systems, at z=0.2378 and z=0.5247, with spin temperatures (Ts) of 2050 +- 200 K and 330 +- 70 K respectively. The non-detection of absorption in the third (candidate) system places an upper limit on its optical depth, which in turn implies a 3sigma lower limit of 850 K on its spin temperature. Ground based K-band imaging observations (Turnshek et al. 2000) have identified the low Ts absorber with a spiral galaxy while the high Ts system appears to be an LSB galaxy. This continues the trend noted earlier by Chengalur and Kanekar (2000) of low spin temperatures for DLAS associated with spiral galaxies and high spin temperatures for those with no such association. Combining these new results with 21cm observations from the published literature, we find that (1)The 21 cm equivalent width (EW21) of DLAS increases with increasing column density (NHI). Further, absorbers associated with spiral galaxies have systematically higher EW21 at the same NHI than DLAS with no such association, (2)DLAS at high redshift (z > 2) have small velocity spreads (DeltaV), while, at low redshift (z < 2), both large and small DeltaV are observed. These trends are in qualitative agreement with hierarchical models of galaxy formation., Comment: (8pages, 7 figures, accepted for publication in A&A)

We report a deep search for 21 cm emission/absorption from the $z \sim 0.101$ candidate damped Lyman-$\alpha$ system towards PKS 0439-433, using the Australia Telescope Compact Array (ATCA). The spectrum shows a weak absorption feature --- at the $3.3 \sigma$ level --- which yields a lower limit of 730 K on the spin temperature of the system. No HI emission was detected: the $3\sigma$ upper limit on the HI mass of the absorber is $2.25 \times 10^9 M_{\odot}$, for a velocity spread of $\sim 70$ km s$^{-1}$. The low HI mass and the high spin temperature seem to rule out the possibility that the absorber is a large gas-rich spiral galaxy., Comment: 5 pages, 4 figures. Accepted by Astronomy and Astrophysics

We present Giant Metrewave Radio Telescope HI 21cm absorption observations, of candidate and confirmed damped Lyman-$\alpha$ systems (DLAS). The derived spin temperatures (T_s) are in all cases $\sim 1000$ K or higher. We have also collated from the literature a list of DLAS for which 21cm observations exist, and discuss their implications for the nature of the absorbers. A cross-comparison of the 21cm profiles with low ionization metal profiles shows that the 21cm absorption coincides in velocity with the deepest metal line feature. This is consistent with models in which the deep metal line features arise from discrete clouds but not with models where the deepest features are the result of velocity crowding. We also find that the typical derived spin temperatures of DLAS are considerably higher than those in the Galaxy or nearby spirals. The only exceptions are DLAS which are known to be associated with the disks of spirals; these do, in fact, show low spin temperatures. In a multi-phase medium,the derived T_s is a weighted average of the temperatures of the individual phases. High derived T_s values are hence to be expected from small, low metallicity objects, since these objects should have a lower fraction of the cold phase in their ISM as compared to large galaxies. The high T_s in DLAS is hence consistent with their observed low metallicities as well as with recent observations that DLAS are also associated with dwarf/LSB galaxies. Finally, we suggest that the following trend may be identified: at low redshift, damped absorption arises from a range of systems, including spiral galaxy disks, while, at high redshift, absorption occurs predominantly in smaller systems. (Abridged), Comment: 7 pages, 2 figures

We have made HI 21cm-line absorption measurements using the GMRT towards 15 directions in the Galaxy which are known to have high random velocity clouds as seen in the optical absorption lines of CaII and NaI. For the first time, in 6 out of these 15 directions we detect HI absorption features corresponding to the high random velocity optical absorption lines. The mean optical depth of these detections is ~ 0.08., Comment: 2 pages, no figures, uses newpasp.sty, contributed talk at IAU Symposium 199 "The Universe at Low Radio Frequencies", held in Pune, Dec. 1999

We report on WSRT observations of HI and OH absorption at z=0.885 towards the radio lens PKS 1830-21, mm wave transitions of several molecular species have already been observed at this redshift. At mm wavelengths the source structure is dominated by two extremely compact components, the northeast (NE) and southwest (SW) components. At lower frequencies the continuum emission is much more extended and there is also a broad Einstein ring connecting the NE and SW components. This means that the HI and OH spectra sample a much larger region of the absorber than the mm wave spectra. The HI spectrum that we obtain is asymmetric, with a peak at -147 km/s with respect to the main molecular line redshift of z=0.88582. Weak mm wave molecular absorption has also been detected towards the NE component at this same velocity. The HI absorption, however, covers a total velocity width of 300 km/sec, i.e. including velocities well to the red of molecular features suggesting that it is spatially widespread. In OH we detect both the 1667 and the 1665 MHz transitions. The OH spectrum has a velocity width comparable to that of the HI spectrum, suggesting that it too is widespread in the absorber. The lack of a prominent HI peak in the spectrum at the velocity corresponding to the SW component, suggests that the galaxy responsible for the absorption at z=0.885 has a central molecular disk many kpc in size, and that HI is deficient in this central region. Our observations are sensitive to the large scale kinematics of the absorber, and to first order the implied dynamical mass is consistent with the lens models of Nair et. al. (1993)., Comment: 4 pages, 3 figures

We present Giant Metrewave Radio Telescope (GMRT) observations of redshifted HI 21cm absorption in two low redshift (z=0.2212, z=0.0912) damped Lyman-alpha systems seen towards the gigahertz peaked source OI 363 (z_em = 0.630). The object at z=0.0912 is the lowest redshift damped Lyman-alpha system known to date. Ground based imaging (Rao & Turnshek, 1998) shows that at neither redshift is there a large spiral galaxy at low impact parameter to the line of sight to OI 363, in contradiction with the suggestion that these systems are large proto-disks. Since OI 363 is a highly compact, core dominated source, the covering factor of the HI gas is likely to be unity. Nonetheless, the spin temperatures derived from the 21cm optical depth (and using the N_HI measured from HST spectra, Rao & Turnshek, 1998) are high, viz. 1120 +/- 200 K and 825 +/- 110 K for the high and low redshift systems respectively. These values are considerably higher than typical values (100 - 200 K) measured in our Galaxy and Andromeda and are, in fact, similar to those obtained in high redshift damped Lyman-alpha systems. Our observations hence suggest that evolutionary effects may not be crucial in understanding the difference in derived spin temperature values between local spiral disks and high redshift damped Lyman-alpha systems., Comment: 4 pages, 2 figures, accepted for publication in MNRAS (letters)

We report a deep radio search with the Ooty Radio Telescope (ORT) for the redshifted 21 cm absorption line from the damped Lyman alpha system seen at redshift 3.388 against the quasar PKS 0201+113. This is currently the most distant system for which a detection of 21 cm absorption has been claimed. The present observations have a sensitivity comparable to the earlier ones and detect no statistically significant absorption. We use the non-detection to place an upper limit of ~ 0.011 on the optical depth of the damped Lyman alpha absorber. This corresponds to a lower limit of ~ 5600 K to the spin temperature of the system. This is considerably higher than the previous upper limit of ~ 1380 K., Comment: 5 pages, 1 figure. Accepted by MNRAS

We report on a deep search with the Westerbork Synthesis Radio Telescope towards the galactic anticenter for the 327 MHz hyperfine transition of DI. This is a favorable direction for a search because: (i) the HI optical depth is high due to velocity crowding; (ii) the observed molecular column density is low (implying that most of the deuterium would probably be in atomic form, rather than in HD); and (iii) the stellar reprocessing should be minimal. Our observations are about a factor of two more sensitive than previous searches for DI in this direction. We detect a low significance (about 4 sigma) feature, consistent in both amplitude and center frequency with an emission feature reported previously (Blitz & Heiles 1987). If this is the DI line, then the implied N_D/N_H of 3.9+/-1.0 x 10^-5 is comparable to the inferred pre-solar deuterium abundance. Our observation is consistent with the recent low measurements of D/H towards high-redshift Lyman-limit systems. On the other hand, if the reports of high DI abundance (about 24 x 10^-5) in such systems are confirmed, then our observations imply that even in regions of reduced star formation within the outer Galaxy, the DI abundance has been reduced by a factor of about 6 from the primordial abundance., Comment: 4 page LaTeX requires l-aa.sty and psfig.sty, 1 ps figure. Accepted for publication in A&A Letters

Ground based optical observations have yielded considerable information on the statistics of damped-lyman alpha systems. In particular these systems are known to be the dominant repository of the observed neutral gas at high redshift. However, particularly at high redshift, there is the possibility that optical observations could be biased due to the exclusion of damped-lyman alpha systems that contain moderate to significant amounts of dust. Independent observational constraints on the neutral hydrogen content at high redshifts and the amount of dust in high redshift systems can be obtained from a radio search against the bright lobes of distant radio galaxies (which is less affected by the presence of dust in foreground damped-lyman alpha systems). We describe here a pilot radio survey along the line of sight to a small sample of high redshift radio galaxies, and also present some preliminary results. The survey uses a novel observing mode at the WSRT which enables one to make sensitive searches of a large redshift interval in a modest amount of telescope time., Comment: A version with figures is available at http://www.nfra.nl/~chengalu/ To appear in "Cold Gas at High Redshift", Eds. M.Bremer et al. (Kluwer, Dordrecht)