7 It is interesting to note that in the case of elastic DM scattering cross-sections σ$_{n}$ ∼ 10 − 43 cm 2 evade the WD bounds [58]. It is unlikely that observations of WDs much cooler than those in M4 will be made as the low lumi- nosity cut-off has been observed, and the luminosity of WDs is limited by the age of the Universe. Therefore it is unlikely that limits from WDs will ever compete with direct detection limits for weak-scale elastic DM. However WDs constitute unique DM probes for three reasons: however numerous possibilities exist for future study of DM capture in WDs. Examples would include DM with mass splittings of the order a few MeV or DM which scat- ters through a light mediator, m$_{φ}$ ∼ MeV, which could be enhanced in WDs through the propagator 1 / ( q 2 − m 2 $_{φ}$). Finally we note that if DM were to be discovered in future experiments, and details of the DM-nucleon cross- section and annihilation products were to be established, then cold WDs could be used to determine an upper limit on the DM density within M4, thus giving clues as to the formation of globular clusters. We thank Andy Eyre and Brad Hansen for conversa- tions and John March-Russell for suggesting the inves- tigation of iDM capture in astrophysical objects. We are also grateful to Maurizio Salaris for conversations and providing the WD data. MM is supported by an STFC Postgraduate Studentship and both MF and MM acknowledge support from the EU Marie Curie Network UniverseNet (HPRN-CT-2006-035863). We have only considered iDM capture in this work, VIII. ACKNOWLEDGEMENTS • The large escape velocity enables in-falling DM particles to easily overcome inelastic splittings and leads to large energy transfers in scattering. • The low mass of carbon gives WDs sensitivity to light DM scenarios, where most direct detection ex- periments lose sensitivity. • Limits from capture in the Sun arise due to neu- trino annihilation products and are therefore insen- sitive to DM annihilating to e $^{+}$e $^{−}$, µ $^{+}$µ $^{−}$, γγ , light hadrons or gluons. It is specifically this scenario where limits from WDs are strongest. [1] I. V. Moskalenko and L. L. Wai, Astrophys. J. 659 , L29 (2007), astro-ph/0702654. [2] G. Bertone and M. Fairbairn, Phys. Rev. D77 , 043515 (2008), 0709.1485. [3] D. Tucker-Smith and N. Weiner, Phys. Rev. D64 , 043502 (2001), hep-ph/0101138. [4] D. Tucker-Smith and N. Weiner, Phys. Rev. D72 , 063509 (2005), hep-ph/0402065. [5] S. Chang, G. D. Kribs, D. Tucker-Smith, and N. Weiner (2008), 0807.2250. [6] R. Bernabei et al., Riv. Nuovo Cim. 26N1 , 1 (2003), astro-ph/0307403. [7] R. Bernabei et al. (DAMA), Eur. Phys. J. C56 , 333 (2008), 0804.2741. [8] S. Nussinov, L.-T. Wang, and I. Yavin (2009), 0905.1333. [9] A. Menon, R. Morris, A. Pierce, and N. Weiner (2009), 0905.1847. [10] J. Shu, P.-f. Yin, and S.-h. Zhu (2010), 1001.1076. [11] J. March-Russell, C. McCabe, and M. McCullough (2009), 0911.4489. [12] N. Arkani-Hamed, D. P. Finkbeiner, T. R. Slatyer, and N. Weiner, Phys. Rev. D79 , 015014 (2009), 0810.0713. [13] O. Adriani et al. (PAMELA), Nature 458 , 607 (2009), 0810.4995. [14] A. A. Abdo et al. (The Fermi LAT), Phys. Rev. Lett. 102 , 181101 (2009), 0905.0025. [15] L. R. Bedin et al., Astrophys. J. 697 , 965 (2009), 0903.2839. [16] L. R. Bedin et al., Mon. Not. Roy. Astron. Soc. 357 , 1038 (2005), astro-ph/0412328. [17] E. E. Salpeter, The Astrophysical Journal 134 , 669 (1961). [18] P. J. E. Peebles, Astrophys. J. 277 , 470 (1984). [19] G. Meylan and C. Pryor (1992), proceedings of the Work- shop on Structure and Dynamics of Globular Clusters, Berkeley, 15-17 July 1992. [20] B. Moore, Astrophys. J. 461 , L13 (1996), astro- ph/9511147. [21] P. Cote, M. J. West, and R. O. Marzke (2001), astro- ph/0111388. [22] L. Gao, S. D. M. White, A. Jenkins, F. Stoehr, and V. Springel, Mon. Not. Roy. Astron. Soc. 355 , 819 (2004), astro-ph/0404589. [23] S. Mashchenko and A. Sills, Astrophys. J. 619 , 258 (2005), astro-ph/0409606. [24] B. Moore, J. Diemand, P. Madau, M. Zemp, and J. Stadel, Mon. Not. Roy. Astron. Soc. 368 , 563 (2006), astro-ph/0510370. [25] T. R. Saitoh, J. Koda, T. Okamoto, K. Wada, and A. Habe, Astrophys. J. 640 , 22 (2006), astro- ph/0511692. [26] B. F. Griffen, M. J. Drinkwater, P. A. Thomas, J. C. Helly, and K. A. Pimbblet (2009), 0910.0310. [27] J. P. Brodie and J. Strader, Ann. Rev. Astron. Astrophys. 44 , 193 (2006), astro-ph/0602601. [28] G. Zaharija, Phys. Rev. D 78 , 027301 (2008). [29] M. Wood et al. (2008), 0801.1708. [30] S. Colafrancesco, S. Profumo, and P. Ullio, As- tron.Astrophys. 455 , 21 (2006), arXiv:astro-ph/0507575. [31] S. Mashchenko and A. Sills, Astrophys. J. 619 , 243 (2005), astro-ph/0409605. [32] J. F. Navarro, C. S. Frenk, and S. D. M. White, Astro- phys. J. 490 , 493 (1997), astro-ph/9611107. [33] G. R. Blumenthal, S. M. Faber, R. Flores, and J. R.