University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Two Ultra-faint Milky Way Stellar Systems Discovered in Early Data from the DECam Local Volume Exploration Survey

Mau, S., Cerny, W., Pace, A. B., Choi, Y., Drlica-Wagner, A., Santana-Silva, L., Riley, A. H., Erkal, D., Stringfellow, G. S., Adamów, M. , Carlin, J. L., Gruendl, R. A., Hernandez-Lang, D., Kuropatkin, N., Li, T. S., Martínez-Vázquez, C. E., Morganson, E., Mutlu-Pakdil, B., Neilsen, E. H., Nidever, D. L., Olsen, K. A. G., Sand, D. J., Tollerud, E. J., Tucker, D. L., Yanny, B., Zenteno, A., Allam, S., Barkhouse, W. A., Bechtol, K., Bell, E. F., Balaji, P., Crnojević, D., Esteves, J., Ferguson, P. S., Gallart, C., Hughes, A. K., James, D. J., Jethwa, P., Johnson, L. C., Kuehn, K., Majewski, S., Mao, Y.-Y., Massana, P., McNanna, M., Monachesi, A., Nadler, E. O., Noel, N.E.D, Palmese, A., Paz-Chinchon, F., Pieres, A., Sanchez, J., Shipp, N., Simon, J. D., Soares-Santos, M., Tavangar, K., van der Marel, R. P., Vivas, A. K., Walker, A. R. and Wechsler, R. H. (2020) Two Ultra-faint Milky Way Stellar Systems Discovered in Early Data from the DECam Local Volume Exploration Survey The Astrophysical Journal, 890 (2), 136.

Full text not available from this repository.


We report the discovery of two ultra-faint stellar systems found in early data from the DECam Local Volume Exploration survey (DELVE). The first system, Centaurus I (DELVE J1238–4054), is identified as a resolved overdensity of old and metal-poor stars with a heliocentric distance of ${\text{}}{D}_{\odot }={116.3}_{-0.6}^{+0.6}\,\mathrm{kpc}$, a half-light radius of ${r}_{h}={2.3}_{-0.3}^{+0.4}\,\mathrm{arcmin}$, an age of $\tau \gt 12.85\,\mathrm{Gyr}$, a metallicity of $Z={0.0002}_{-0.0002}^{+0.0001}$, and an absolute magnitude of ${M}_{V}=-{5.55}_{-0.11}^{+0.11}\,\mathrm{mag}$. This characterization is consistent with the population of ultra-faint satellites and confirmation of this system would make Centaurus I one of the brightest recently discovered ultra-faint dwarf galaxies. Centaurus I is detected in Gaia DR2 with a clear and distinct proper motion signal, confirming that it is a real association of stars distinct from the Milky Way foreground; this is further supported by the clustering of blue horizontal branch stars near the centroid of the system. The second system, DELVE 1 (DELVE J1630–0058), is identified as a resolved overdensity of stars with a heliocentric distance of ${\text{}}{D}_{\odot }={19.0}_{-0.6}^{+0.5}\,\mathrm{kpc}$, a half-light radius of ${r}_{h}={0.97}_{-0.17}^{+0.24}\,\mathrm{arcmin}$, an age of $\tau ={12.5}_{-0.7}^{+1.0}\,\mathrm{Gyr}$, a metallicity of $Z={0.0005}_{-0.0001}^{+0.0002}$, and an absolute magnitude of ${M}_{V}=-{0.2}_{-0.6}^{+0.8}\,\mathrm{mag}$, consistent with the known population of faint halo star clusters. Given the low number of probable member stars at magnitudes accessible with Gaia DR2, a proper motion signal for DELVE 1 is only marginally detected. We compare the spatial position and proper motion of both Centaurus I and DELVE 1 with simulations of the accreted satellite population of the Large Magellanic Cloud (LMC) and find that neither is likely to be associated with the LMC.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Physics
Authors :
Mau, S.
Cerny, W.
Pace, A. B.
Choi, Y.
Drlica-Wagner, A.
Santana-Silva, L.
Riley, A. H.
Erkal, D.
Stringfellow, G. S.
Adamów, M.
Carlin, J. L.
Gruendl, R. A.
Hernandez-Lang, D.
Kuropatkin, N.
Li, T. S.
Martínez-Vázquez, C. E.
Morganson, E.
Mutlu-Pakdil, B.
Neilsen, E. H.
Nidever, D. L.
Olsen, K. A. G.
Sand, D. J.
Tollerud, E. J.
Tucker, D. L.
Yanny, B.
Zenteno, A.
Allam, S.
Barkhouse, W. A.
Bechtol, K.
Bell, E. F.
Balaji, P.
Crnojević, D.
Esteves, J.
Ferguson, P. S.
Gallart, C.
Hughes, A. K.
James, D. J.
Jethwa, P.
Johnson, L. C.
Kuehn, K.
Majewski, S.
Mao, Y.-Y.
Massana, P.
McNanna, M.
Monachesi, A.
Nadler, E. O.
Palmese, A.
Paz-Chinchon, F.
Pieres, A.
Sanchez, J.
Shipp, N.
Simon, J. D.
Soares-Santos, M.
Tavangar, K.
van der Marel, R. P.
Vivas, A. K.
Walker, A. R.
Wechsler, R. H.
Date : 21 January 2020
Funders : University of Chicago Provost’s Scholar Award, NSF, CON-ICYT FONDECYT
DOI : 10.3847/1538-4357/ab6c67
Grant Title : NSF
Copyright Disclaimer : © 2020. The American Astronomical Society. All rights reserved.
Projects : NASA Fermi Guest Investigator Program Cycle 9, Fermilab LDRD
Additional Information : Embargo OK Metadata OK No Further Action
Depositing User : James Marshall
Date Deposited : 20 Aug 2020 15:07
Last Modified : 20 Aug 2020 15:07

Actions (login required)

View Item View Item


Downloads per month over past year

Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800