The Latest from the VLA

In the following, we present some new observations that we recently obtained at the VLA in B array configuration (D. Riechers, PhD Thesis, MPIA Heidelberg).

APM0827+5255 (z = 3.9): The presence of extended C0(1-0) emission in APM0827+5255 was reported by Papadopoulus et al. (2001). Additional C0(2-1)

Fig. 2. Image of C0(1-0) towards APM 08729+5255 obtained with the VLA covering a bandwidth of 43.75MHz, or 560km s-1 (Riechers et al. 2006, in prep.). Contours are shown at -3, -2, 2, 3, 4, 5, 6, 7, and 8 xa (1a = 16 ^Jy beam-1. The beam size (0.30" x 0.30") is shown in the bottom left corner. We find no evidence for an extended reservoir of molecular gas around this source.

Fig. 2. Image of C0(1-0) towards APM 08729+5255 obtained with the VLA covering a bandwidth of 43.75MHz, or 560km s-1 (Riechers et al. 2006, in prep.). Contours are shown at -3, -2, 2, 3, 4, 5, 6, 7, and 8 xa (1a = 16 ^Jy beam-1. The beam size (0.30" x 0.30") is shown in the bottom left corner. We find no evidence for an extended reservoir of molecular gas around this source.

C-array imaging by Papadopoulus et al. also showed some evidence for an extended envelope around the central QSO. We have have obtained new C and B array observations for this source and do not find evidence for such an extended CO component. In Fig. 2, we show our highest resolution data, where we detect a compact but resolved structure of the lens images. Two clearly separated images can be seen, and their morphology and brightess ratio is very similar to that of the optical QSO. We thus conclude that the CO in this source is indeed extremely compact, and that the lensing magnification is close to the optical magnification i.e., a factor of 100 rather than 7 as derived in previous models (Lewis et al. 2002). Further evidence against an extended C0(1-0) reservoir around APM0827+5255 comes from our multi-CO transition study of this source (Weiss et al. 2006, in prep., see also this volume, and recent single dish observations of this source using the GBT, Riechers et al. 2006, see also this volume).

B1335-0417 (z = 4.4): This is one of the first sources detected in CO(2-1) with the VLA in D array (Carilli et al. 1999). We recently re-observed the CO(2-1) transition in the z = 4.4 QSO BRI1335-0417 at high resolution (0.15") with the VLA in B-array (Fig. 3, Riechers et al. 2006, in prep.). The integrated CO map shows a compact but resolved molecular gas reservoir, and our velocity channel maps show, for the first time, the actual dynamics of the molecular gas in a high-z QSO host galaxy at high signal-to-noise. The detected structure shows an interesting morphology which may be interpreted as a close merger or rotation. We are currently modeling the kinematics of this unique dataset.

13 3803-48 03 46 03. M 03.« 03.40 03.38 03.36 RIGHT ASCENSION [J2000]

Fig. 3. Image of CO(2-1) towards BRI1335-0417 obtained with the VLA. top: Moment 0 map covering a bandwidth of 43.75 MHz, or 300 km s-1 (Riechers et al. 2006, in prep.). Contours are shown at -2, 2, 4, 6, 8, and 10 xa (1a = 50 ^Jy beam-1. bottom: Channel maps with a width of 12.5 MHz, or 85 km s-1 each, covering the central 260 km s-1 of the emission. Contours are shown at -3, -2, 2, 3, 4, 5, 6, 7, and 8 xa (1a = 100 ¡j,Jy beam-1). For the first time these observations allow us to study the kinematics in a high-z QSO host galaxy in detail.

Fig. 3. Image of CO(2-1) towards BRI1335-0417 obtained with the VLA. top: Moment 0 map covering a bandwidth of 43.75 MHz, or 300 km s-1 (Riechers et al. 2006, in prep.). Contours are shown at -2, 2, 4, 6, 8, and 10 xa (1a = 50 ^Jy beam-1. bottom: Channel maps with a width of 12.5 MHz, or 85 km s-1 each, covering the central 260 km s-1 of the emission. Contours are shown at -3, -2, 2, 3, 4, 5, 6, 7, and 8 xa (1a = 100 ¡j,Jy beam-1). For the first time these observations allow us to study the kinematics in a high-z QSO host galaxy in detail.

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