Definitive Identification of the Transition between Small- to Large-Scale Clustering for Lyman Break Galaxies

We report angular correlation function (ACF) of Lyman Break Galaxies (LBGs) with unprecedented statistical quality on the basis of 16,920 LBGs at z=4 detected in the 1 deg^2 sky of the Subaru/XMM-Newton Deep Field. The ACF significantly departs from a power law, and shows an excess on small scale. Particularly, the ACF of LBGs with i'<27.5 have a clear break between the small and large-scale regimes at the angular separation of ~7'' whose projected length corresponds to the virial radius of dark halos with a mass of 10^11-12 Mo, indicating multiple LBGs residing in a single dark halo. Both on small (2''<theta<3'') and large (40''<theta<400'') scales, clustering amplitudes monotonically increase with luminosity for the magnitude range of i'=24.5-27.5, and the small-scale clustering shows a stronger luminosity dependence than the large-scale clustering. The small-scale bias reaches b~10-50, and the outskirts of small-scale excess extend to a larger angular separation for brighter LBGs. The ACF and number density of LBGs can be explained by the cold dark matter model.Comment: Accepted for publication in ApJL. 5 pages, 4 figures. The text and Figures 2-4 have been revised. There is no major change which affects to the main discussion shown in the original preprint. This paper with high resolution figures is available at http://www-int.stsci.edu/~ouchi/work/astroph/sxds_z4LBG/ouchi_highres.pdf (PDF

The Subaru/XMM-Newton Deep Survey (SXDS) -VII. Clustering Segregation with Ultraviolet and Optical Luminosities of Lyman-Break Galaxies at z~3

We investigate clustering properties of Lyman-break galaxies (LBGs) at z~3 based on deep multi-waveband imaging data from optical to near-infrared wavelengths in the Subaru/XMM-Newton Deep Field. The LBGs are selected by U-V and V-z' colors in one contiguous area of 561 arcmin^2 down to z'=25.5. We study the dependence of the clustering strength on rest-frame UV and optical magnitudes, which can be indicators of star formation rate and stellar mass, respectively. The correlation length is found to be a strong function of both UV and optical magnitudes with brighter galaxies being more clustered than faint ones in both cases. Furthermore, the correlation length is dependent on a combination of UV and optical magnitudes in the sense that galaxies bright in optical magnitude have large correlation lengths irrespective of UV magnitude, while galaxies faint in optical magnitude have correlation lengths decreasing with decreasing UV brightness. These results suggest that galaxies with large stellar masses always belong to massive halos in which they can have various star formation rates, while galaxies with small stellar masses reside in less massive halos only if they have low star formation rates. There appears to be an upper limit to the stellar mass and the star formation rate which is determined by the mass of hosting dark halos.Comment: 16 pages, 15 figures, accepted for publication in Ap

Luminosity dependent clustering of star-forming BzK galaxies at redshift 2

We use the BzK color selection proposed by Daddi et al. (2004) to obtain a sample of 1092 faint star-forming galaxies (hereafter sBzKs) from 180 arcmin^2 in the Subaru Deep Field. This sample represents star-forming galaxies at 1.4 < z < 2.5 down to K(AB)=23.2, which roughly corresponds to a stellar-mass limit of ~ 1 x 10^{10} Msun. We measure the angular correlation function (ACF) of these sBzKs to be w(theta) = (0.58 +- 0.13) x theta["]^{-0.8} and translate the amplitude into the correlation length assuming a reasonable redshift distribution. The resulting value, r0 = 3.2^{+0.6}_{-0.7} h^{-1} Mpc, suggests that our sBzKs reside in haloes with a typical mass of 2.8 x 10^{11} Msun. Combining this halo mass estimate with those for brighter samples of Kong et al. (2006), we find that the mass of dark haloes largely increases with K brightness, a measure of the stellar mass. Comparison with other galaxy populations suggests that faint sBzKs (K(AB)<23.2) and Lyman Break Galaxies at z ~ 2 are similar populations hosted by relatively low-mass haloes, while bright sBzKs (K(AB)<21) reside in haloes comparable to or more massive than those of Distant Red Galaxies and Extremely Red Objects. Using the extended Press-Schechter formalism, we predict that present-day descendants of haloes hosting sBzKs span a wide mass range depending on K brightness, from lower than that of the Milky Way up to those of richest clusters.Comment: 14 pages, 9 figures, accepted for publication in Ap

A Double Planetary System around the Evolved Intermediate-Mass Star HD 4732

We report the detection of a double planetary system orbiting around the evolved intermediate-mass star HD 4732 from precise Doppler measurements at Okayama Astrophysical Observatory (OAO) and Anglo-Australian Observatory (AAO). The star is a K0 subgiant with a mass of 1.7 M_sun and solar metallicity. The planetary system is composed of two giant planets with minimum mass of msini=2.4 M_J, orbital period of 360.2 d and 2732 d, and eccentricity of 0.13 and 0.23, respectively. Based on dynamical stability analysis for the system, we set the upper limit on the mass of the planets to be about 28 M_J (i>5 deg) in the case of coplanar prograde configuration.Comment: 12 pages, 7 figures, accepted for publication in Ap

Medulloblastoma with suprasellar solitary massive metastasis: Case report

It is extremely rare for metastasised medulloblastoma to form a large tumour in the suprasellar region. We present a case of medulloblastoma with large suprasellar metastasis at initial presentation. A 3-year and 5-month-old boy presented with a 1-month history of vomiting and loss of appetite, and body weight. Computed tomography and magnetic resonance imaging revealed a 20mm×20mm mass in the suprasellar region and a 30mm×30mm mass in the fourth cerebral ventricle. We performed endoscopic biopsy of the suprasellar tumour, and subsequently totally removed the vermian tumour through a suboccipital craniotomy. The histopathological findings revealed that both the suprasellar and vermian tumours were classic type and non SHH/WNT type medulloblastoma. The postoperative course was uneventful. The patient showed complete remission after chemotherapy. The tumour in the suprasellar region was most likely metastatic from the vermis. Endoscopic biopsy of the tumour in the suprasellar region and total removal of the tumour in the vermis in a one-stage operation followed by intensive chemotherapy with reduced dose radiotherapy may provide a satisfactory outcome

Acute non-heparin-induced thrombocytopenia during hemodiafiltration in a patient with multiple myeloma

This report demonstrates that not only heparin‐induced thrombocytopenia, but also hemodialysis conditions (platelet activation due to hemodiafiltration and heparin underdosing) may markedly reduce the platelet count and cause clotting in the hemodialysis circuit in patients in a hypercoagulable state. The clot prevention effects of bortezomib are therefore of great importance