The halo of M 49 and its environment as traced by planetary nebulae populations

Hartke, Johanna; Arnaboldi, M.; Longobardi, A.; Gerhard, Ortwin; Freeman, K. C.; Okamura, S.; Nakata, Fumiaki

doi:10.1051/0004-6361/201730463

Cited by 34 publications

(85 citation statements)

References 90 publications

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“…Such sharp transitions are not expected in relaxed clusters. For example, around M49 in the Virgo subcluster B, the BCG plus IGL system displays a continuous radial transition in both kinematics and stellar population properties (Hartke et al 2018).…”

Section: The Virgo Icl An Unrelaxed Component In the Cluster Corementioning

confidence: 99%

Kinematics of the outer halo of M 87 as mapped by planetary nebulae

Longobardi

Arnaboldi

Gerhard

et al. 2018

A&A

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Aims. We present a kinematic study of a sample of 298 planetary nebulas (PNs) in the outer halo of the central Virgo galaxy M87 (NGC 4486). The line-of-sight velocities of these PNs are used to identify sub-components, to measure the angular momentum content of the main M87 halo, and to constrain the orbital distribution of the stars at these large radii. Methods. We use Gaussian mixture modelling to statistically separate distinct velocity components and identify the M87 smooth halo component, its unrelaxed substructures, and the intra-cluster (IC) PNs. We compute probability weighted velocity and velocity dispersion maps for the smooth halo, and its specific angular momentum profile (λ R ) and velocity dispersion profile. Results. The classification of the PNs into smooth halo and ICPNs is supported by their different PN luminosity functions. Based on a K-S test, we conclude that the ICPN line-of-sight velocity distribution (LOSVD) is consistent with the LOSVD of the galaxies in Virgo subcluster A. The surface density profile of the ICPNS at 100 kpc radii has a shallow logarithmic slope, −α ICL ≃ −0.8, dominating the light at the largest radii. Previous B-V colour and resolved star metallicity data indicate masses for the ICPN progenitor galaxies of a few ×10 8 M ⊙ . The angular momentum-related λ R profile for the smooth halo remains below 0.1, in the slow rotator regime, out to 135 kpc average ellipse radius (170 kpc major axis distance). Combining the PN velocity dispersion measurements for the M87 halo with literature data in the central 15 kpc, we obtain a complete velocity dispersion profile out to R avg = 135 kpc. The σ halo profile decreases from the central 400 kms −1 to about 270 kms −1 at 2-10 kpc, then rises again to ≃ 300 ± 50 kms −1 at 50-70 kpc to finally decrease sharply to σ halo ∼ 100 kms −1 at R avg = 135 kpc. The steeply decreasing outer σ halo profile and the surface density profile of the smooth halo can be reconciled with the circular velocity curve inferred from assuming hydrostatic equilibrium for the hot X-ray gas. Because this rises to v c,X ∼ 700 kms −1 at 200 kpc, the orbit distribution of the smooth M87 halo is required to change strongly from approximately isotropic within R avg ∼ 60 kpc to very radially anisotropic at the largest distances probed. Conclusions. The extended LOSVD of the PNs in the M87 halo allows the identification of several subcomponents: the ICPNs, the "crown" accretion event, and the smooth M87 halo. In galaxies like M87, the presence of these sub-components needs to be taken into account to avoid systematic biases in estimating the total enclosed mass. The dynamical structure inferred from the velocity dispersion profile indicates that the smooth halo of M87 steepens beyond R avg = 60 kpc and becomes strongly radially anisotropic, and that the velocity dispersion profile is consistent with the X-ray circular velocity curve at these radii without non-thermal pressure effects.

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Section: The Virgo Icl An Unrelaxed Component In the Cluster Corementioning

confidence: 99%

Kinematics of the outer halo of M 87 as mapped by planetary nebulae

Longobardi

Arnaboldi

Gerhard

et al. 2018

A&A

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“…The faint end of the PNLF has been shown to vary considerably, depending on the details of the stellar population. It is seen to be correlated with the star formation history of the parent stellar population, with steeper slopes associated with older stellar populations and conversely flatter slopes with younger populations (Ciardullo et al 2004;Ciardullo 2010;Longobardi et al 2013;Hartke et al 2017). The changes in the PNLF slope can result from the superposition of multiple stellar populations, which can then be disentangled using the PNe kinematics (Longobardi et al 2015;Hartke et al 2018).…”

Section: Introductionmentioning

confidence: 96%

“…Because of their relatively strong [O iii] 5007 Å emission, PNe can be readily identified. They have been shown to be efficient tracers of stellar light in different galaxies like M 87 (Longobardi et al 2013), M 49 (Hartke et al 2017), and many other early-type galaxies (Coccato et al 2009;Cortesi et al 2013;Pulsoni et al 2018). The luminosity-specific PN number (α-parameter) varies slightly with B − V colour of galaxies with higher values for late-type galaxies and lower values for early-type galaxies (Buzzoni et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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The survey of planetary nebulae in Andromeda (M 31)

Bhattacharya

Arnaboldi

Hartke

et al. 2019

A&A

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Context. The Andromeda (M 31) galaxy subtends nearly 100 square degrees on the sky. Any study of its halo must therefore account for the severe contamination from the Milky Way halo stars whose surface density displays a steep gradient across the entire M 31 field of view. Aims. Our goal is to identify a population of stars firmly associated with the M 31 galaxy. Planetary nebulae (PNe) are one such population that are excellent tracers of light, chemistry, and motion in galaxies. We present a 16 square degree survey of the disc and inner halo of M 31 with the MegaCam wide-field imager at the CFHT to identify PNe, and characterise the luminosity-specific PN number and PN luminosity function (PNLF) in M 31. Methods. PNe were identified via automated detection techniques based on their bright [O iii] 5007 Å emission and absence of a continuum. Subsamples of the faint PNe were independently confirmed by matching with resolved Hubble Space Telescope sources from the Panchromatic Hubble Andromeda Treasury and spectroscopic follow-up observations with HectoSpec at the MMT. Results. The current survey reaches two magnitudes fainter than the previous most sensitive survey. We thus identify 4289 PNe, of which only 1099 were previously known. By comparing the PN number density with the surface brightness profile of M 31 out to ∼30 kpc along the minor axis, we find that the stellar population in the inner halo has a luminosity-specific PN number value that is seven times higher than that of the disc. We measure the luminosity function of the PN population and find a bright cut-off and a slope consistent with previous determinations. Interestingly, it shows a significant rise at the faint end, present in all radial bins covered by the survey. This rise in the M 31 PNLF is much steeper than that observed for the Magellanic clouds and Milky Way bulge. Conclusions. The significant radial variation of the PN specific frequency value indicates that the stellar population at deprojected minor-axis radii larger than ∼10 kpc is different from that in the disc of M 31. The rise at the faint end of the PNLF is a property of the late phases of the stellar population. M 31 shows two major episodes of star formation and the rise at the faint end of the PNLF is possibly associated with the older stellar population. It may also be a result of varying opacity of the PNe.

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“…The α in the main galaxy halo and intracluster light (ICL) or intragroup light (IGL) of M87 and M49 were from Longobardi et al (2015) and Hartke et al (2017). The metallicities of M87's halo and ICL were adopted from Longobardi et al (2015) and those of M49 were from Hartke et al (2017) (upper limit of metallicities in ICL/IGL). The metallicities of GCs in this work were calculated through the GC color-metallicity empirical relation adapted to Virgo galaxies M49 and M87 derived by Peng et al (2006).…”

Section: α In Globular Clusters and Galaxiesmentioning

confidence: 99%

The Next Generation Virgo Cluster Survey. XVII. A Search for Planetary Nebulae in Virgo Cluster Globular Clusters

Sun

Peng

et al. 2019

ApJ

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The occurrence of planetary nebulae (PNe) in globular clusters (GCs) provides an excellent chance to study low-mass stellar evolution in a special (low-metallicity, high stellar density) environment. We report a systematic spectroscopic survey for the [Oiii] 5007Å emission line of PNe in 1469 Virgo GCs and 121 Virgo ultra-compact dwarfs (UCDs), mainly hosted in the giant elliptical galaxies M87, M49, M86, and M84. We detected zero PNe in our UCD sample and discovered one PN (M 5007 = −4.1 mag) associated with an M87 GC. We used the [Oiii] detection limit for each GC to estimate the luminosityspecific frequency of PNe, α, and measured α in the Virgo cluster GCs to be α ∼ 3.9 +5.2 −0.7 ×10 −8 PN/L . α in Virgo GCs is among the lowest values reported in any environment, due in part to the large sample size, and is 5-6 times lower than that for the Galactic GCs. We suggest that α decreases towards brighter and more massive clusters, sharing a similar trend as the binary fraction, and the discrepancy between the Virgo and Galactic GCs can be explained by the observational bias in extragalactic surveys toward brighter GCs. This low but non-zero efficiency in forming PNe may highlight the important role played by binary interactions in forming PNe in GCs. We argue that a future survey of less massive Virgo GCs will be able to determine whether PN production in Virgo GCs is governed by internal process (mass, density, binary fraction), or is largely regulated by external environment.

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The halo of M 49 and its environment as traced by planetary nebulae populations

Cited by 34 publications

References 90 publications

Kinematics of the outer halo of M 87 as mapped by planetary nebulae

Kinematics of the outer halo of M 87 as mapped by planetary nebulae

The survey of planetary nebulae in Andromeda (M 31)

The Next Generation Virgo Cluster Survey. XVII. A Search for Planetary Nebulae in Virgo Cluster Globular Clusters

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