Abstract
We present two pieces of evidence supporting the hypothesis that the bright [O III] λ5007 sources found in Virgo's intracluster space are intracluster planetary nebulae rather than [O II] λ3727 galaxies at z ∼ 0.35 or Lyα sources at z ∼ 3.13. First, we confirm the nature of five "overluminous" [O III] sources that are postulated to lie in front of M87: by examining the composite spectrum of these objects, we show that the weaker [O III] line at λ4959 is definitely present at a strength ∼1/3 that of [O III] λ5007. The ratio demonstrates that, at most, only one of the five objects is a background galaxy. We then estimate the surface density of background emission-line objects by conducting a wide-field (0.13 deg2) search at λ5019 for faint emission-line sources in a "blank field" located well away from any galaxy or cluster. We show that the density of blank-field emission-line sources is significantly lower than the density of sources detected between the galaxies of Virgo but in good agreement with the density of Lyα galaxies found by Hu, Cowie, & McMahon. The implication is that background galaxies account for only ∼20% of the planetary nebula candidates in Virgo's intracluster fields.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 784-793 |
| Number of pages | 10 |
| Journal | Astrophysical Journal |
| Volume | 566 |
| Issue number | 2 I |
| DOIs | |
| State | Published - Feb 20 2002 |
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All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
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A measurement of the contamination in [O III] λ5007 surveys of intracluster stars and the surface density of z = 3.13 Lyα galaxies. / Ciardullo, Robin; Feldmeier, John J.; Krelove, Kara; Jacoby, George H.; Gronwall, Caryl.
In: Astrophysical Journal, Vol. 566, No. 2 I, 20.02.2002, p. 784-793.Research output: Contribution to journal › Article
TY - JOUR
T1 - A measurement of the contamination in [O III] λ5007 surveys of intracluster stars and the surface density of z = 3.13 Lyα galaxies
AU - Ciardullo, Robin
AU - Feldmeier, John J.
AU - Krelove, Kara
AU - Jacoby, George H.
AU - Gronwall, Caryl
PY - 2002/2/20
Y1 - 2002/2/20
N2 - We present two pieces of evidence supporting the hypothesis that the bright [O III] λ5007 sources found in Virgo's intracluster space are intracluster planetary nebulae rather than [O II] λ3727 galaxies at z ∼ 0.35 or Lyα sources at z ∼ 3.13. First, we confirm the nature of five "overluminous" [O III] sources that are postulated to lie in front of M87: by examining the composite spectrum of these objects, we show that the weaker [O III] line at λ4959 is definitely present at a strength ∼1/3 that of [O III] λ5007. The ratio demonstrates that, at most, only one of the five objects is a background galaxy. We then estimate the surface density of background emission-line objects by conducting a wide-field (0.13 deg2) search at λ5019 for faint emission-line sources in a "blank field" located well away from any galaxy or cluster. We show that the density of blank-field emission-line sources is significantly lower than the density of sources detected between the galaxies of Virgo but in good agreement with the density of Lyα galaxies found by Hu, Cowie, & McMahon. The implication is that background galaxies account for only ∼20% of the planetary nebula candidates in Virgo's intracluster fields.
AB - We present two pieces of evidence supporting the hypothesis that the bright [O III] λ5007 sources found in Virgo's intracluster space are intracluster planetary nebulae rather than [O II] λ3727 galaxies at z ∼ 0.35 or Lyα sources at z ∼ 3.13. First, we confirm the nature of five "overluminous" [O III] sources that are postulated to lie in front of M87: by examining the composite spectrum of these objects, we show that the weaker [O III] line at λ4959 is definitely present at a strength ∼1/3 that of [O III] λ5007. The ratio demonstrates that, at most, only one of the five objects is a background galaxy. We then estimate the surface density of background emission-line objects by conducting a wide-field (0.13 deg2) search at λ5019 for faint emission-line sources in a "blank field" located well away from any galaxy or cluster. We show that the density of blank-field emission-line sources is significantly lower than the density of sources detected between the galaxies of Virgo but in good agreement with the density of Lyα galaxies found by Hu, Cowie, & McMahon. The implication is that background galaxies account for only ∼20% of the planetary nebula candidates in Virgo's intracluster fields.
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U2 - 10.1086/338230
DO - 10.1086/338230
M3 - Article
AN - SCOPUS:0038190829
VL - 566
SP - 784
EP - 793
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2 I
ER -