Diffuse Light in Galaxy Diffuse Light in Galaxy GroupsGroups

Nieves D. Castro-RodríguezNieves D. Castro-Rodríguez11, J. Alfonso L. , J. Alfonso L. AguerriAguerri11, Magda Arnaboldi, Magda Arnaboldi22, Ortwin Gerhard, Ortwin Gerhard33

11Instituto de Astrofísica de CanariasInstituto de Astrofísica de Canarias22Osservatorio Astronomico di Pino TorineseOsservatorio Astronomico di Pino Torinese

33Astronomisches Institut der Universitat BaselAstronomisches Institut der Universitat Basel

Gdansk Gdansk 20052005

OutlineOutline

Diffuse LightDiffuse Light General characteristicsGeneral characteristics Detection of diffuse lightDetection of diffuse light Clusters and groupsClusters and groups

Leo GroupLeo Group HGC 44HGC 44 ConclusionsConclusions

Diffuse Light:Diffuse Light:Coma Cluster (Zwicky, 1951) as an excess of light Coma Cluster (Zwicky, 1951) as an excess of light among galaxies.among galaxies.Its nature and content has been a mistery during Its nature and content has been a mistery during decades due to its low surface brightness (decades due to its low surface brightness (BB=28 mag =28 mag arcsecarcsec-2-2).).It has been detected by different tracers: It has been detected by different tracers: Globular Globular clustersclusters ( (West et al. 1995, Jordán et al. 2003West et al. 1995, Jordán et al. 2003), ), SNeSNe ((Gal-Yam et al. 2003Gal-Yam et al. 2003), ), RGBRGB ( (Ferguson et al. 1998Ferguson et al. 1998), ), ICPNeICPNe ( (Arnaboldi et al. 1998Arnaboldi et al. 1998).).Nature Harassment (Moore et al. 1996)Nature Harassment (Moore et al. 1996)Simulations tell us that DL depends on the mass of the Simulations tell us that DL depends on the mass of the cluster (Murante et al. 2004). The more massive cluster (Murante et al. 2004). The more massive clusters have the largest fraction of diffuse light.clusters have the largest fraction of diffuse light.

Virgo Cluster:Virgo Cluster:

Virgo:Virgo: Diffuse Diffuse light in the Core light in the Core is clumpy and is clumpy and represents about represents about 10% of the total 10% of the total light. (Arnaboldi light. (Arnaboldi et al. 2002; et al. 2002; Aguerri et al. Aguerri et al. 2005).2005).

Fornax: Fornax: (Theuns & Warren (Theuns & Warren

1997)1997)

Studied Core Fields In Virgo ClusterAguerri et al. (2005)

Groups of Galaxies:Groups of Galaxies:

Diffuse light fraction less than that seen Diffuse light fraction less than that seen in rich clusters. Observations in M81 in rich clusters. Observations in M81 group (Feldmeier et al. 2003): less than group (Feldmeier et al. 2003): less than 3% of the total stellar luminosity.3% of the total stellar luminosity.

In general, diffuse light in groups of In general, diffuse light in groups of galaxies is not deep studied.galaxies is not deep studied.

Fraction of stellar massFraction of stellar massin diffuse light vs. cluster in diffuse light vs. cluster mass (Murante et al. 2004) .mass (Murante et al. 2004) .

OIII filter and B/V (on-OIII filter and B/V (on-off band technique)off band technique)

Contaminants:Contaminants: HII regions in the HII regions in the

clustercluster [OII] emitters at [OII] emitters at

Z~0.34Z~0.34 LyLy emitters at emitters at

z~3.1z~3.1

Arnaboldi et al. 2002

For details: For details:

M. Arnaboldi (previous talk)M. Arnaboldi (previous talk)

Planetary Nebulae Planetary Nebulae Method:Method:

Leo Group:Leo Group:

HI emission ring discovered HI emission ring discovered by Schneider et al. 1983, and by Schneider et al. 1983, and the localization of our initial the localization of our initial candidatescandidates

Color Magnitude Diagram Color Magnitude Diagram There are 29 candidates There are 29 candidates (Castro-Rodríguez et al. 2003)(Castro-Rodríguez et al. 2003)

*Luminosity Function of the *Luminosity Function of the selected emission line selected emission line candidates in the Leo Field. candidates in the Leo Field. *This LF is compared with the *This LF is compared with the PNe LF in the Leo galaxies.PNe LF in the Leo galaxies.*PNe as standard candles*PNe as standard candles (Ciardullo et al. 2002)(Ciardullo et al. 2002)

Luminosity Function Luminosity Function (LF):(LF):

The LF of the PNe have been used as distance indicators in late and early galaxies (Ciardullo et al. 2002).The bright cut-off of our objects is 1.2 mag fainter that the PNLF of the main galaxy in Leo.

Luminosity function of field LyLuminosity function of field Ly emitters at emitters at z~3.1 In our effective volume z~3.1 In our effective volume (Castro-(Castro-

Rodríguez et al. 2003)Rodríguez et al. 2003)::

Continuous line is the Continuous line is the expected LF of the Lyexpected LF of the Ly population at z~3.1 from population at z~3.1 from Steidel et al. (2000). Steidel et al. (2000). Filled dots indicated the Filled dots indicated the LyLy in the Blank-Field in the Blank-Field survey by Cowie & Hu survey by Cowie & Hu (1998), and asterisks are (1998), and asterisks are spectroscopically spectroscopically confirmed Lyconfirmed Ly emitters from emitters from Kudritzki et al. (2000) Kudritzki et al. (2000)

Background Contaminants -------------- Blank FieldBackground Contaminants -------------- Blank Field

Upper limit of the diffuse lightUpper limit of the diffuse lightin Leo: < 1.6%in Leo: < 1.6%

Spectroscopic Spectroscopic Confirmation:Confirmation:

Two-Dimensional spectraTwo-Dimensional spectraof some emission line of some emission line candidates with the VLTcandidates with the VLT

One-Dimensional spectra of two One-Dimensional spectra of two IGPNe candidates. The LyIGPNe candidates. The Ly emission is emission is visible in both objects.visible in both objects.

HCG44:HCG44:

B band image of HGC 44 from B band image of HGC 44 from INT Telescope (La Palma,INT Telescope (La Palma,Spain)Spain)

Color Magnitude Diagram, followingthe PNe method (Arnaboldi et al. 2002)There are 12 candidates.

Aguerri et al. 2005Aguerri et al. 2005

Hickson Group with high Hickson Group with high HI deficiency HI deficiency (Verdes-Montenegro et al. (2001))(Verdes-Montenegro et al. (2001))

LF of the IGPNe photometrical candidates (full squares). LF of the IGPNe photometrical candidates (full squares). Is also overlaped the LF of the LyIs also overlaped the LF of the Ly objects from: objects from: Castro-Rodríguez et al. (2003); Aguerri et al. (2005); Castro-Rodríguez et al. (2003); Aguerri et al. (2005); Kudritzki et al. (2000); Ciardullo et al. (2002).Kudritzki et al. (2000); Ciardullo et al. (2002).

All of the All of the candidates candidates Are compatible Are compatible with Lywith LyBackground Background galaxies!!!!galaxies!!!!

Upper limit of Upper limit of the diffuse the diffuse lightlightin HCG: < in HCG: < 0.24%0.24%

Conclusions:Conclusions:

We have study the IGL in two galaxy groups: Leo We have study the IGL in two galaxy groups: Leo and HGC44.and HGC44.

The emission line objects detected in both groups The emission line objects detected in both groups have a LF compatible with Lyhave a LF compatible with Ly emitters emitters . .

This gives an upper limit of diffuse light in those This gives an upper limit of diffuse light in those groups of 1-3%.groups of 1-3%.

This number is much smaller than the detected in This number is much smaller than the detected in more massive clusters like the core region of more massive clusters like the core region of VIrgo cluster.VIrgo cluster.

The detected emission line objects can be used The detected emission line objects can be used for background contamination in similar studies.for background contamination in similar studies.

Before all the wondrous shows of the widespread space around him, what living, Before all the wondrous shows of the widespread space around him, what living, sentient thing loves not the all-joyous light -- with its colors, its rays and sentient thing loves not the all-joyous light -- with its colors, its rays and

undulations, its gentle omnipresence in the form of the wakening Day? The undulations, its gentle omnipresence in the form of the wakening Day? The giant-world of the unresting constellations inhales it as the innermost soul giant-world of the unresting constellations inhales it as the innermost soul of life, and floats dancing in its blue flood -- the sparkling, ever-tranquil of life, and floats dancing in its blue flood -- the sparkling, ever-tranquil

stone, the thoughtful, imbibing plant, and the wild, burning multiform beast stone, the thoughtful, imbibing plant, and the wild, burning multiform beast inhales it -- but more than all, the lordly stranger with the sense-filled inhales it -- but more than all, the lordly stranger with the sense-filled

eyes, the swaying walk, and the sweetly closed, melodious lips. Like a king eyes, the swaying walk, and the sweetly closed, melodious lips. Like a king over earthly nature, it rouses every force to countless transformations, binds over earthly nature, it rouses every force to countless transformations, binds

and unbinds innumerable alliances, hangs its heavenly form around every earthlyand unbinds innumerable alliances, hangs its heavenly form around every earthlysubstance. -- Its presence alone reveals the marvelous splendor of the kingdoms substance. -- Its presence alone reveals the marvelous splendor of the kingdoms

of the world. of the world.   

(Novalis, Friedrich von Hardenberg, "Hymns to the Night" )(Novalis, Friedrich von Hardenberg, "Hymns to the Night" )