Presentation on theme: "14 Sep 2006NVO Summer School 20061 T HE US N ATIONAL V IRTUAL O BSERVATORY Shape of Galaxy Rotation Curves A multiwavelength study using the VO Barbara."— Presentation transcript:
14 Sep 2006NVO Summer School 20061 T HE US N ATIONAL V IRTUAL O BSERVATORY Shape of Galaxy Rotation Curves A multiwavelength study using the VO Barbara Catinella, Arecibo Obs. Luca Cortese, Cardiff Univ. Chris Springob, Naval Research Lab.
14 Sep 2006NVO Summer School 20062 Rotation Curves (RCs)
14 Sep 2006NVO Summer School 20063 SFI++ RC sample SFI++ I-band photometry+ Hi/H spectroscopy sample, collected by Cornell Univ. ExtraGalactic Group (EGG) to study the peculiar velocity field in the local universe using the Tully-Fisher relation (TFR) Largest sample of RCs to date (N~3000) Red: early type galaxies ( Sb ) Blue: late type galaxies ( Sbc)
14 Sep 2006NVO Summer School 20064 Our Project Make the RC dataset available through the VO –Convert the RC files into VOTable format –Make a MySQL database –Make a web interface to access and query the data Cross-match our dataset with others available through the NVO Study the dependence of RC parameters on galaxy properties at different wavelengths
14 Sep 2006NVO Summer School 20065 Making the data available to the VO Made VOTables using VOConvert MySQL database
14 Sep 2006NVO Summer School 20066 Web interface (HTML/PHP)
14 Sep 2006NVO Summer School 200610 Cross-match with other datasets using the VO Springob et al. 2005 HI archive -> VO (B. Kent) SDSS DR5 -> SDSS website 2MASS XSC -> OpenSkyQuery Used topcat to x-match datasets and look for correlations between RC parameters and photometric quantities
14 Sep 2006NVO Summer School 200611 Results: TFR in K band
14 Sep 2006NVO Summer School 200612 Results: TFR at different s TFR is steeper at redder s holds true for both SDSS and 2MASS consistent with results from the literature (Sakai et al. 2000; Pizagno et al. 2006) Dependence is consistent with expectations, as dimmer galaxies tend to be bluer, which means shallower slope at blue s Scatter is relatively independent of waveband for 2MASS, but increases for bluer bands in SDSS. In contrast, Pizagno et al. 2006 says SDSS TF scatter is independent of waveband
14 Sep 2006NVO Summer School 200613 Results: SBs vs. RC widths Brighter galaxies have larger widths, as expected Scatter in the SB relations is larger than in the L relations
14 Sep 2006NVO Summer School 200614 Results: SBs vs. RC widths Brighter galaxies have larger widths, as expected Scatter in the SB relations is larger than in the L relations
14 Sep 2006NVO Summer School 200615 Scientific conclusions We find no significant relationship between the outer slope of the RCs and optical/NIR photometric parameters. On the other hand, rotational widths are strongly correlated with photometric parameters. Those correlations show that: –more massive galaxies are brighter and redder--no surprises –TF scatter is greater at bluer wavelengths (at least for SDSS bands) –All other things being equal, TFR should be a better distance indicator in redder bands – in contradiction with the results of Pizagno et al. 2006
14 Sep 2006NVO Summer School 200616 Future work Publish the RC data set to the VO Refine the analysis presented here, applying corrections to the photometric quantities (e.g., extinction) Obtain average RCs in SB intervals at different s using 2MASS and SDSS data Present these fantastic results at the AAS meeting in Seattle using the NVOs $500 check
14 Sep 2006NVO Summer School 200617 Conclusions: what we learned from the NVO SS We learned and demonstrated how to: make VOTables, MySQL databases, and web interface to access our data set cross-match our RC database with 3 large datasets Use the power of the VO to obtain science results… at light speed!!!
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