Ultracompact dwarf galaxies in Abell 1689: A photometric study with the advanced camera for surveys

S. Mieske; L. Infante; N. Benítez; D. Coe; J. P. Blakeslee; K. Zekser; H. C. Ford; T. J. Broadhurst; G. D. Illingworth; G. F. Hartig; M. Clampin; D. R. Ardila; F. Bartko; R. J. Bouwens; R. A. Brown; C. J. Burrows; E. S. Cheng; N. J.G. Cross; P. D. Feldman; M. Franx; D. A. Golimowski; T. Goto; C. Gronwall; B. Holden; N. Homeier; R. A. Kimble; J. E. Krist; M. P. Lesser; A. R. Martel; F. Menanteau; G. R. Meurer; G. K. Miley; M. Postman; P. Rosati; M. Sirianni; W. B. Sparks; H. D. Tran; Z. I. Tsvetanov; R. L. White; W. Zheng

doi:10.1086/423701

Ultracompact dwarf galaxies in Abell 1689: A photometric study with the advanced camera for surveys

S. Mieske^*, L. Infante, N. Benítez, D. Coe, J. P. Blakeslee, K. Zekser, H. C. Ford, T. J. Broadhurst, G. D. Illingworth, G. F. Hartig, M. Clampin, D. R. Ardila, F. Bartko, R. J. Bouwens, R. A. Brown, C. J. Burrows, E. S. Cheng, N. J.G. Cross, P. D. Feldman, M. FranxD. A. Golimowski, T. Goto, C. Gronwall, B. Holden, N. Homeier, R. A. Kimble, J. E. Krist, M. P. Lesser, A. R. Martel, F. Menanteau, G. R. Meurer, G. K. Miley, M. Postman, P. Rosati, M. Sirianni, W. B. Sparks, H. D. Tran, Z. I. Tsvetanov, R. L. White, W. Zheng

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

45 Citations (Scopus)

Abstract

The properties of ultracompact dwarf (UCD) galaxy candidates in Abell 1689 (z = 0.183) are investigated, based on deep high-resolution images from the Hubble Space Telescope Advanced Camera for Surveys. A UCD candidate has to be unresolved, have i < 28 mag (M_V < -11.5 mag), and satisfy color limits derived from Bayesian photometric redshifts. We find 160 UCD candidates with 22 mag < i < 28 mag. We estimate that about 100 of these are cluster members, based on their spatial distribution and photometric redshifts. For i ≲ 26.8 mag, the radial and luminosity distribution of the UCD candidates can be explained well by Abell 1689's globular cluster (GC) system. For i ≲ 26.8 mag, there is an overpopulation of 15 ± 5 UCD candidates with respect to the GC luminosity function. For i ≲ 26 mag, the radial distribution of UCD candidates is more consistent with the dwarf galaxy population than with the GC system of Abell 1689. The UCD candidates follow a color-magnitude trend with a slope similar to that of Abell 1689's genuine dwarf galaxy population, but shifted fainter by about 2-3 mag. Two of the three brightest UCD candidates (M_V ≃ -17 mag) are slightly resolved. At the distance of Abell 1689, these two objects would have King profile core radii of ≃35 pc and r_eff ≃ 300 pc, implying luminosities and sizes 2-3 times those of M32's bulge. Additional photometric redshifts obtained with late-type stellar and elliptical galaxy templates support the assignment of these two resolved sources to Abell 1689 but also allow for up to four foreground stars among the six brightest UCD candidates. Our findings imply that in Abell 1689 there are ≥10 UCDs with M_V < -12.7 mag, probably created by stripping "normal" dwarf or spiral galaxies. Compared with the UCDs in the Fornax Cluster - the location of their original discovery - they are brighter, larger, and have colors closer to normal dwarf galaxies. This suggests that they may be in an intermediate stage of the stripping process. Checking the photometric redshifts of the brightest UCD candidates with spectroscopy would be the next step to definitely confirm the existence of UCDs in Abell 1689.

Original language	English
Pages (from-to)	1529-1540
Number of pages	12
Journal	Astronomical Journal
Volume	128
Issue number	4
DOIs	https://doi.org/10.1086/423701
Publication status	Published - Oct 2004
Externally published	Yes

Keywords

Galaxies: clusters: individual (Abell 1689)
Galaxies: dwarf
Galaxies: fundamental parameters
Galaxies: nuclei
Globular clusters: general

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10.1086/423701

Cite this

Mieske, S., Infante, L., Benítez, N., Coe, D., Blakeslee, J. P., Zekser, K., Ford, H. C., Broadhurst, T. J., Illingworth, G. D., Hartig, G. F., Clampin, M., Ardila, D. R., Bartko, F., Bouwens, R. J., Brown, R. A., Burrows, C. J., Cheng, E. S., Cross, N. J. G., Feldman, P. D., ... Zheng, W. (2004). Ultracompact dwarf galaxies in Abell 1689: A photometric study with the advanced camera for surveys. Astronomical Journal, 128(4), 1529-1540. https://doi.org/10.1086/423701

@article{6529c21f7a8d4f73a99ab1d6a121444d,

title = "Ultracompact dwarf galaxies in Abell 1689: A photometric study with the advanced camera for surveys",

abstract = "The properties of ultracompact dwarf (UCD) galaxy candidates in Abell 1689 (z = 0.183) are investigated, based on deep high-resolution images from the Hubble Space Telescope Advanced Camera for Surveys. A UCD candidate has to be unresolved, have i < 28 mag (MV < -11.5 mag), and satisfy color limits derived from Bayesian photometric redshifts. We find 160 UCD candidates with 22 mag < i < 28 mag. We estimate that about 100 of these are cluster members, based on their spatial distribution and photometric redshifts. For i ≲ 26.8 mag, the radial and luminosity distribution of the UCD candidates can be explained well by Abell 1689's globular cluster (GC) system. For i ≲ 26.8 mag, there is an overpopulation of 15 ± 5 UCD candidates with respect to the GC luminosity function. For i ≲ 26 mag, the radial distribution of UCD candidates is more consistent with the dwarf galaxy population than with the GC system of Abell 1689. The UCD candidates follow a color-magnitude trend with a slope similar to that of Abell 1689's genuine dwarf galaxy population, but shifted fainter by about 2-3 mag. Two of the three brightest UCD candidates (MV ≃ -17 mag) are slightly resolved. At the distance of Abell 1689, these two objects would have King profile core radii of ≃35 pc and reff ≃ 300 pc, implying luminosities and sizes 2-3 times those of M32's bulge. Additional photometric redshifts obtained with late-type stellar and elliptical galaxy templates support the assignment of these two resolved sources to Abell 1689 but also allow for up to four foreground stars among the six brightest UCD candidates. Our findings imply that in Abell 1689 there are ≥10 UCDs with MV < -12.7 mag, probably created by stripping {"}normal{"} dwarf or spiral galaxies. Compared with the UCDs in the Fornax Cluster - the location of their original discovery - they are brighter, larger, and have colors closer to normal dwarf galaxies. This suggests that they may be in an intermediate stage of the stripping process. Checking the photometric redshifts of the brightest UCD candidates with spectroscopy would be the next step to definitely confirm the existence of UCDs in Abell 1689.",

keywords = "Galaxies: clusters: individual (Abell 1689), Galaxies: dwarf, Galaxies: fundamental parameters, Galaxies: nuclei, Globular clusters: general",

author = "S. Mieske and L. Infante and N. Ben{\'i}tez and D. Coe and Blakeslee, {J. P.} and K. Zekser and Ford, {H. C.} and Broadhurst, {T. J.} and Illingworth, {G. D.} and Hartig, {G. F.} and M. Clampin and Ardila, {D. R.} and F. Bartko and Bouwens, {R. J.} and Brown, {R. A.} and Burrows, {C. J.} and Cheng, {E. S.} and Cross, {N. J.G.} and Feldman, {P. D.} and M. Franx and Golimowski, {D. A.} and T. Goto and C. Gronwall and B. Holden and N. Homeier and Kimble, {R. A.} and Krist, {J. E.} and Lesser, {M. P.} and Martel, {A. R.} and F. Menanteau and Meurer, {G. R.} and Miley, {G. K.} and M. Postman and P. Rosati and M. Sirianni and Sparks, {W. B.} and Tran, {H. D.} and Tsvetanov, {Z. I.} and White, {R. L.} and W. Zheng",

year = "2004",

month = oct,

doi = "10.1086/423701",

language = "English",

volume = "128",

pages = "1529--1540",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "4",

}

Mieske, S, Infante, L, Benítez, N, Coe, D, Blakeslee, JP, Zekser, K, Ford, HC, Broadhurst, TJ, Illingworth, GD, Hartig, GF, Clampin, M, Ardila, DR, Bartko, F, Bouwens, RJ, Brown, RA, Burrows, CJ, Cheng, ES, Cross, NJG, Feldman, PD, Franx, M, Golimowski, DA, Goto, T, Gronwall, C, Holden, B, Homeier, N, Kimble, RA, Krist, JE, Lesser, MP, Martel, AR, Menanteau, F, Meurer, GR, Miley, GK, Postman, M, Rosati, P, Sirianni, M, Sparks, WB, Tran, HD, Tsvetanov, ZI, White, RL & Zheng, W 2004, 'Ultracompact dwarf galaxies in Abell 1689: A photometric study with the advanced camera for surveys', Astronomical Journal, vol. 128, no. 4, pp. 1529-1540. https://doi.org/10.1086/423701

TY - JOUR

T1 - Ultracompact dwarf galaxies in Abell 1689

T2 - A photometric study with the advanced camera for surveys

AU - Mieske, S.

AU - Infante, L.

AU - Benítez, N.

AU - Coe, D.

AU - Blakeslee, J. P.

AU - Zekser, K.

AU - Ford, H. C.

AU - Broadhurst, T. J.

AU - Illingworth, G. D.

AU - Hartig, G. F.

AU - Clampin, M.

AU - Ardila, D. R.

AU - Bartko, F.

AU - Bouwens, R. J.

AU - Brown, R. A.

AU - Burrows, C. J.

AU - Cheng, E. S.

AU - Cross, N. J.G.

AU - Feldman, P. D.

AU - Franx, M.

AU - Golimowski, D. A.

AU - Goto, T.

AU - Gronwall, C.

AU - Holden, B.

AU - Homeier, N.

AU - Kimble, R. A.

AU - Krist, J. E.

AU - Lesser, M. P.

AU - Martel, A. R.

AU - Menanteau, F.

AU - Meurer, G. R.

AU - Miley, G. K.

AU - Postman, M.

AU - Rosati, P.

AU - Sirianni, M.

AU - Sparks, W. B.

AU - Tran, H. D.

AU - Tsvetanov, Z. I.

AU - White, R. L.

AU - Zheng, W.

PY - 2004/10

Y1 - 2004/10

N2 - The properties of ultracompact dwarf (UCD) galaxy candidates in Abell 1689 (z = 0.183) are investigated, based on deep high-resolution images from the Hubble Space Telescope Advanced Camera for Surveys. A UCD candidate has to be unresolved, have i < 28 mag (MV < -11.5 mag), and satisfy color limits derived from Bayesian photometric redshifts. We find 160 UCD candidates with 22 mag < i < 28 mag. We estimate that about 100 of these are cluster members, based on their spatial distribution and photometric redshifts. For i ≲ 26.8 mag, the radial and luminosity distribution of the UCD candidates can be explained well by Abell 1689's globular cluster (GC) system. For i ≲ 26.8 mag, there is an overpopulation of 15 ± 5 UCD candidates with respect to the GC luminosity function. For i ≲ 26 mag, the radial distribution of UCD candidates is more consistent with the dwarf galaxy population than with the GC system of Abell 1689. The UCD candidates follow a color-magnitude trend with a slope similar to that of Abell 1689's genuine dwarf galaxy population, but shifted fainter by about 2-3 mag. Two of the three brightest UCD candidates (MV ≃ -17 mag) are slightly resolved. At the distance of Abell 1689, these two objects would have King profile core radii of ≃35 pc and reff ≃ 300 pc, implying luminosities and sizes 2-3 times those of M32's bulge. Additional photometric redshifts obtained with late-type stellar and elliptical galaxy templates support the assignment of these two resolved sources to Abell 1689 but also allow for up to four foreground stars among the six brightest UCD candidates. Our findings imply that in Abell 1689 there are ≥10 UCDs with MV < -12.7 mag, probably created by stripping "normal" dwarf or spiral galaxies. Compared with the UCDs in the Fornax Cluster - the location of their original discovery - they are brighter, larger, and have colors closer to normal dwarf galaxies. This suggests that they may be in an intermediate stage of the stripping process. Checking the photometric redshifts of the brightest UCD candidates with spectroscopy would be the next step to definitely confirm the existence of UCDs in Abell 1689.

AB - The properties of ultracompact dwarf (UCD) galaxy candidates in Abell 1689 (z = 0.183) are investigated, based on deep high-resolution images from the Hubble Space Telescope Advanced Camera for Surveys. A UCD candidate has to be unresolved, have i < 28 mag (MV < -11.5 mag), and satisfy color limits derived from Bayesian photometric redshifts. We find 160 UCD candidates with 22 mag < i < 28 mag. We estimate that about 100 of these are cluster members, based on their spatial distribution and photometric redshifts. For i ≲ 26.8 mag, the radial and luminosity distribution of the UCD candidates can be explained well by Abell 1689's globular cluster (GC) system. For i ≲ 26.8 mag, there is an overpopulation of 15 ± 5 UCD candidates with respect to the GC luminosity function. For i ≲ 26 mag, the radial distribution of UCD candidates is more consistent with the dwarf galaxy population than with the GC system of Abell 1689. The UCD candidates follow a color-magnitude trend with a slope similar to that of Abell 1689's genuine dwarf galaxy population, but shifted fainter by about 2-3 mag. Two of the three brightest UCD candidates (MV ≃ -17 mag) are slightly resolved. At the distance of Abell 1689, these two objects would have King profile core radii of ≃35 pc and reff ≃ 300 pc, implying luminosities and sizes 2-3 times those of M32's bulge. Additional photometric redshifts obtained with late-type stellar and elliptical galaxy templates support the assignment of these two resolved sources to Abell 1689 but also allow for up to four foreground stars among the six brightest UCD candidates. Our findings imply that in Abell 1689 there are ≥10 UCDs with MV < -12.7 mag, probably created by stripping "normal" dwarf or spiral galaxies. Compared with the UCDs in the Fornax Cluster - the location of their original discovery - they are brighter, larger, and have colors closer to normal dwarf galaxies. This suggests that they may be in an intermediate stage of the stripping process. Checking the photometric redshifts of the brightest UCD candidates with spectroscopy would be the next step to definitely confirm the existence of UCDs in Abell 1689.

KW - Galaxies: clusters: individual (Abell 1689)

KW - Galaxies: dwarf

KW - Galaxies: fundamental parameters

KW - Galaxies: nuclei

KW - Globular clusters: general

UR - http://www.scopus.com/inward/record.url?scp=9344251089&partnerID=8YFLogxK

U2 - 10.1086/423701

DO - 10.1086/423701

M3 - Article

AN - SCOPUS:9344251089

SN - 0004-6256

VL - 128

SP - 1529

EP - 1540

JO - Astronomical Journal

JF - Astronomical Journal

IS - 4

ER -

Ultracompact dwarf galaxies in Abell 1689: A photometric study with the advanced camera for surveys

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Keywords

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