1. Protoplanetary discs of isolated VLMOs discovered in the IPHAS survey Luisa Valdivielso (IAC) ‏ Collaborators: E. Martín, H. Bouy, E. Solano, J.Drew, R. Greimel, B. Riaz 10/09/2009 lval@iac.es

2. 2 Aims lval@iac.es Search young low mass objects on the IPHAS survey Spectral type (SpT) classification with low resolution spectroscopy of the targets Study the chromosferic/accretion activity measuring the H  equivalent width NaI doublet (818.3nm, 819.5nm) equivalent width as surface gravity indicator Distance estimation and comparison with known SFR’s Spitzer photometry, SED’s & disc properties L. Valdivielso

3. 3 Outline L. Valdivielso lval@iac.es Introduction Data selection & observations Results Conclusions & perspectives

4. Introduction Very low mass objects and brown dwarfs L. Valdivielso lval@iac.es 4 Many young objects show H  emission due to accretion processes Search in star formation regions such as Chamaeleon,  Oph,  Orionis, Serpens, Taurus, Trapezium… Broadband optical surveys have missed strong Halpha emitters as they appear bluer than they are

5. 5 Introduction: IPHAS Survey lval@iac.es Observations with WFC (Wide Field Camera) on Isaac Newton Telescope Filters: r’ (6240 Å), i’ (7743 Å) Sloan, H  (6568 Å) ‏ Magnitude limit r’ ~20 1800º 2 in the North of the Milky Way: search very low mass objects out of the best known star forming regions L. Valdivielso

6. 6 Data: targets selection lval@iac.es Cross-match of IPHAS with 2MASS (The Two Micron All Sky Survey) catalogue using Aladin: r’, i’, H , J, H, K photometry of the targets Selection criteria for 2MASS sources: a) 0.7<J-H<1.3 discard strong reddened objects and red giants b) 0.5<H-K<1.1 cool photospheres objects and/or infrared excess IPHAS counterparts: a) 1.1<r’-H  <3.0 b) 16<i’<18.5 c) 1.2<r’-i’<2.2 d) 2.9<i’-J<3.5 red objects L. Valdivielso

7. 7 Data: Observations lval@iac.es WHT/ISIS : - Dates: 2006 August 1-2 - 35 targets -t exp : 700-1800s NOT/ALFOSC : Dates: 2006 October 10-14 56 targets t exp : 300-2400s 3m-Shane Telescope/KAST: - Dates: 2007 July 2-5 - 25 targets t exp : 300-2400s L. Valdivielso

8. 8 Results lval@iac.es 116 IPHAS targets observed:  48 real candidates according new IPHAS photometry  42 objects show strong H  emission (success rate > 80%)  12 objects M5.5-M7  30 between M0-M5.5 L. Valdivielso

9. H  vs SpT Barrado y Navascués & Martín (2003) criteria to study the accretion level of the targets. All objects with H  emission show accretion lval@iac.es L. Valdivielso

10. lval@iac.es NaI doublet measurements NaI doublet equivalent width measurements between 8172Å and 8207Å Comparison with field M dwarfs & Upper Sco members (5Myr) ‏ Later type objects show lower surface gravity L. Valdivielso Upper-Sco

11. 11 Spectro-photometric distances lval@iac.es Baraffe Nextgen models log g=4 ; age 5Myr and 2Myr to compute distances SIMBAD search within 30arcmin 16 of them located near molecular clouds, star formation regions and young open clusters: Serpens, North American Nebula, Cep IV, IC1396, Cygnus Some objects not located to any known young association (free- floating ejected from sfr? member of unknown nearby assoc?) L. Valdivielso

12. 12 Spitzer photometry lval@iac.es Search Spitzer data to compute SED’s L. Valdivielso Data avaliable for 17 objects Nº objects with 3.6-24 µm: 9

13. 13 Spitzer photometry lval@iac.es Search Spitzer data to compute SED’s L. Valdivielso Data avaliable for 17 objects Nº objects with 3.6-24 µm: 9 Comparison with  –Oph members

14. 14 Preliminary SED analysis lval@iac.es L. Valdivielso Robitaille SED online-fitting tool for first estimations of disc properties (Robitaille et al. 2007) ‏ Stellar age ~2.5Myr Stellar mass ~0.14M sun Stellar radius ~1.16R sun Stellar Temperature ~3063K Disk mass ~1.63e-4M sun i(deg) ~40-50 SpT M6

15. CONCLUSIONS 15 lval@iac.es L. Valdivielso  VO tools are very efficient to search for very low mass objects and brown dwarfs using large databases  IPHAS survey to detect new objects using optical wavelengths  We spectroscopically detect very low mass objects in different regions studied until now  Most of the objects with H  emission show evidences of accretion processes and very low surface density indicative of youth  Spitzer data show infrared excesses due to protoplanetary discs

16. PERSPECTIVES 16 lval@iac.es L. Valdivielso  Extend this study using the new release of IPHAS  Originally the goal was complement optical surveys but our study proved to be complementary to mid-IR surveys (SPITZER) as well  Study in more detail the properties of the isolated young VLMOs (kinematics, activity, GAIA, HERSCHEL) ‏  This study can be perform in particular regions to see how many objects have been missed

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