IPERCOOL IN MOTION (it’s very proper) A.H. Andrei 1,2,3,4 (also on behalf of Leigh Smith) (1) OATo/INAF - IT (2) ON/MCTI - BR (3) SYRTE/OP - FR (4) OV/UFRJ - BR IPERCOOL BRASIL

Parsec’s Proper Motions Reduction procedure reduction pipeline applied to entire mosaic of 8 CCDs each CCD reduced independently using UCAC2 stars Depending on the number of reference stars the polynomial degree was 2 or 3 and cross terms have been included. The rms errors of the solutions did not show any dependence on the type of the polynomial employed. nearest- neighbor match with 2MASS point source catalogue safety measure: p.m. determined for each observation pair and later averaged while removing deviant values From the first 18 months of the PARSEC observations, it was formed a catalog containing proper motion determinations for 195,700 objects. It samples 42.3 deg of the southern hemisphere with the exception of the lowest galactic latitudes where the number of known L/T dwarfs is significantly reduced. Results median rms error 5 mas/year p.m. distribution histograms in agreement with UCAC2 data IPERCOOL BRASIL

= -2.8 mas (UCAC2 -2.7) = -4.0 mas (UCAC2 -3.6) Pearson’s linear Correlation = 0.95 on RA and on DEC Comparison with UCAC2 IPERCOOL BRASIL

RPM diagram of PARSEC Proper Motion catalogue IPERCOOL BRASIL

Parallaxes – Direct ellipse fitting On the left, the comparison between the proper motions derived from the direct parallactic ellipse fitting and those from the 1.5y PARSEC PM catalog (2MASS as 1 st epoch). The correlation is at 0.9, and PMs are derived for 9 targets that did not belong in the PARSEC PM catalog. Below, the comparison between the parallaxes derived from the direct parallactic ellipse fitting and the initial PARSEC photometric parallax estimate. The linear correlation is weak and the photometric parallaxes are indicated to be overestimated by 24mas on average. IPERCOOL BRASIL

Astrometric Radial Velocity dμ dμ ―― = K. μπV r ―― = K. μπV r dt dt most brown dwarfs have high proper motion and parallax perspective proper motion should thus be integrated to the astrometric pipeline (in special when adding up early positions) conversely the perspective proper motion can indicate stars of high radial velocityResults trigonometric parallaxes known at mas level proper motions known at mas/y level dμ/dt dμ/dt can be known at mas/y/y level 48 PARSEC stars of high enough proper motion all objects can be found in the GSC fields perfect example: k2318s13 ( ) – μ α = mas/y and μ δ =758.9mas/y

IPERCOOL BRASIL Astrometric Radial Velocity

Parallaxes of five L dwarfs with a Robotic Telescope - Youfen Wang et al. IPERCOOL BRASIL Observations at the 2m. Liverpool Telescope (LT) at Roque de Los Muchachos. The LT is a totally robotic telescope, prototype for the two Faulkes robotic telescopes and the 2.4 meter in Yunnan Lijiang Gaomeigu Observatory affiliated to the National Astronomical Observatory of China. The CCD is RATCam 2048x2048, with a pixel scale of arcsec/pixel and a field of view of 4.6 arcmin. The observations were taken in the SDSS-z band filter, between Aug/2004 and Jul/2009, with 3 exposures of 160s to SNR above 50. Before defringing the median rms in the (x,y) coordinates is 21mas for all objects and 13mas for objects brighter than magnitude z=17. Applying the fringe map provided by LT pipeline the precision improves to 12mas and 9mas respectively, but the faintest stars are missed. A system similar of that used by the PARSEC is then used, in which the fringe maps are constructed from the science frames. The (x,y) coordinates were determined by the CASU IMCORE software. The parallaxes and proper motions used the methods adopted in the TOPP (Smart et al. 2003, 2007). It selects the frames and reference stars automatically, dropping frames with less than 6 reference stars. The base frame is selected about the middle of the sequence and with a high number of stars. Using standard coordinated referred to the UCAC2, all frames are placed onto the base using all common stars and a linear transformation.

Parallaxes of five L dwarfs with a Robotic Telescope - Youfen Wang et al. IPERCOOL BRASIL The spatial motion can be described in three components U,V,W respectively radially away from the galactic center, in the direction of galactic rotation, and perpendicular to the galactic disk. The motion of the targets indicates to which galactic component they pertain. Besides the tangential motion, to derive (U,V,W) also the radial velocity is required – normally from high resolution spectroscopy. From the SDSS sample of nearby M dwarfs, we see that the mean velocity is 0km/s and the σ is 30km/s. Thus, radial values of 30, 0, -30 km/s were tested for the targets that have it not measured. The derived (U,V,W) diagram is shown in the plot. As the halo population would have velocities beyond the 2σ ellipsoid, it is concluded that all targets belong to the disk population.

A Two Epochs Proper Motion Catalogue from the UKIDSS LAS – Leigh Smith et al. IPERCOOL BRASIL The UKDISS - United Kingdom Infrared Deep Sky Survey - project began in 2005, and is a 7 year effort to survey roughly 7000 sq.deg. using the 3.8m infrared-dedicated United Kingdom Infra-Red Telescope (UKIRT), situated at Mauna Kea, Hawaii, and the Wide Field CAMera – WFCAM. The UKIDSS is comprised of 5 smaller surveys. Of these, the LAS - Large Area Survey - covers 4028 square degrees in Y, J, H, and K bands to a depth of 18.2 magnitudes in K (complemented by the SDSS ugriz colors). The WFCAM consists of four 2048×2048 px arrays, which combined with UKIRT optics give a total viewing angle of 0.21 sq.deg. (i.e., 0.4arcsec/px). During observation the arrays can be micro-stepped and four individual exposures are taken, each with a 0.5px offset in x and/or y. The images are recombined using interleaving and dribbling. It corrects PSF mismatches caused by changes in the observing conditions between exposures, which can lead to a ‘spiky’ PSF. This process of oversampling improves the resolution of the WFCAM images to the limit of the seeing.

A Two Epochs Proper Motion Catalogue from the UKIDSS LAS – Leigh Smith et al. IPERCOOL BRASIL The catalog uses data from two UKIDSS J-band (LAS) epochs, with a typical baseline 2-4 years. Galaxies were removed through photometry, either by classification or by quality thresholds. The care aims to not contaminate the relative to absolute correction performed at a latter stage. The two epoch (α,δ) positions are converted to tangent plane (ξ, η) standard coordinates relative to the center of their frames. Bright Jmag < 18.1, sources, that also met the photometry quality thresholds, found at the two epochs, define control point pairs - CPPs. An approximate 2nd order transform is calculated using these CPPs. Only CPPs with residuals smaller than 0”.26 are kept. Then a definitive 2nd order transform is calculated within a radius of 1’ surrounding each source. If there are less than 3 CPPs the radius is increased at 20” steps. Sources were separated into 0.1 magnitude bins, the standard deviation of residuals in each bin (for residuals smaller than 45mas - around 80%) is then adopted as the uncertainty on the residual for all sources in the bin. The residuals and associated uncertainties are then propagated through to proper motions and errors using the epoch baseline. To convert the relative proper motions to absolute the median apparent proper motion of the galaxies in each frame and those from surrounding frames within half a degree are then subtracted from the proper motions for all stellar sources in the frame.

IPERCOOL BRASIL A Two Epochs Proper Motion Catalogue from the UKIDSS LAS – Leigh Smith et al. The LSPM catalogue utilizes the SUPERBLINK software to normalize the differences between pairs of sub-frames from the POSS-I and POSS-II. High proper motion sources identified by the SUPERBLINK were removed, and as a result it has minimal false detection. It includes data from TYCHO-2 and the All-Sky Compiled Cat. The LSPM-North was matched to the LAS proper motion catalogue using a 3” matching radius and a 0.5 mag J band discrepancy tolerance. 394 matches are found. The proper motions from both catalogues agree within their 1σ uncertainties for 88% of sources, this rises to 98% agreement at 2σ. The proper motions from the catalogues are also well correlated, with Pearson correlation coefficients of 0.995, and (μRA, μDec and μtotal respectively). One specially discrepant source is analyzed and the photographic measurements are found capable to explain the disagreement.

IPERCOOL BRASIL A Two Epochs Proper Motion Catalogue from the UKIDSS LAS – Leigh Smith et al. The NLTT is a catalog of stars with proper motions larger than 180mas/y. The NLTT catalogue was revised and refined in 2004, giving improved positions and proper motions for sources present in both the original POSSI frames and the second 2MASS data release. The NLTT was matched to the LAS using a 3” matching radius and a 0.5 mag J band discrepancy tolerance, finding 121 matches. It is found that proper motions from both catalogues agree within their 1σ uncertainties for 89% of sources, rising to 94% agreement at 2σ. The Pearson product-moment correlation coefficients are 0.970, and μRA, μDec and μtotal respectively. But, when discarding 6 sources with largest proper motion differences then the correlation coefficients increase to 0.998, and μRA, μDec and μtotal respectively.

IPERCOOL BRASIL A Two Epochs Proper Motion Catalogue from the UKIDSS LAS – Leigh Smith et al. The APOP - Absolute Proper motions Out side the Plane catalogue is built from the GSC2 plate database, by determining local corrections referred to the UCAC system, made absolute by constraining zero motion for galaxies in the plates; the final result was checked against the LQRF. The LAS was matched with the APOP to extend the comparison for much larger number of stars. The color difference (mostly R for the APOP) forced to accept wider intervals for the match. The percentage of matches with proper motions in Right Ascension that agreed within their 1 and 2 sigma errors was 82% to within 1σ And 95.5% to within 2σ. The proper motion agreement in Declination was similar. 26 sources with total proper motion larger than 400mas/y were retained. Their astrometry was revised, as well as their photometry, spectral types, and putative distances – from the best values in the literature. These sources are prime BD candidates for photometric and/or spectroscopic observation.

. IPERCOOL BRASIL 谢谢, See you in Brasil soon