Old stellar Galactic disc in near-plane regions according to 2MASS: Scales, cut-off, flare and warp

López-Corredoira, M.; Cabrera-Lavers, A.; Garzón, F.; Hammersley, P. L.

doi:10.1051/0004-6361:20021175

Cited by 269 publications

(418 citation statements)

References 37 publications

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“…LC01 find counts for m K ≤ 9.0 of approximately 2000 using DENIS data averaged over Δ = 5 • . We can estimate the counts expected by a model, in this case using a similar model as proposed by LC01 with disk density given by López-Corredoira et al (2002, 2004, with the luminosity function proposed by Eaton et al (1984) and the counts in the Galactic bar based on the density distribution proposed by López-Corredoira et al (2007) with the luminosity function considered as an average of the disk and bulge luminosity function. We have obtained counts in good agreement with ones observed by VVV.…”

Section: Discussionmentioning

confidence: 99%

The long bar as seen by the VVV Survey

Amôres

López-Corredoira

González-Fernández

et al. 2013

A&A

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Context. There is still some debate about the presence and the morphological properties of the long bar in the inner Galaxy. Aims. We investigate the morphological properties of the long Galactic bar using the VVV survey extending star counts at least 3 mag deeper than 2MASS. Our study covers the relatively unexplored negative longitudes of the Galactic bar. We obtain a detailed description of the spatial distribution of star counts towards the long Galactic bar as well as to measure its parameters. Methods. We performed star counts towards −20 • < < 0, |b| ≤ 2 • using VVV, 2MASS, and GLIMPSE data. We applied an average interstellar extinction correction. We also adjusted latitudinal profiles to obtain the centroid variation and bar thickness. Results. We probe the structure of long Galactic bar, as well as its far edge at ≈ −14 • . The differences between counts with and without extinction correction allow us to produce a crude extinction map showing regions with high extinction, mainly beyond the end of long Galactic bar. The latitudinal profiles show evidence of the centroid vertical variation with Galactic longitude reaching a minimum at ≈ −13.8 • . The bar has an inclination angle α = 43 • ± 5 • with respect to the line Sun-Galactic center. In addition, we have determined the bar parameters, such as thickness, length, and stellar distribution.

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Section: Discussionmentioning

confidence: 99%

The long bar as seen by the VVV Survey

Amôres

López-Corredoira

González-Fernández

et al. 2013

A&A

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“…The asymmetry of the warp was long identified in HI gas (Burton 1988;Levine et al 2006;Kalberla & Dedes 2008) and even in stars (López-Corredoira et al 2002;Reylé et al 2009). But this is the first time that it is shown that the shape varies with the age of the tracers considered.…”

Section: Dependence Of the Warp Flare And Scale Length With Agementioning

confidence: 98%

“…The evidence comes from gas tracers such as HI (Henderson et al 1982;Burton & te Lintel Hekkert 1986;Burton 1988;Diplas & Savage 1991;Nakanishi & Sofue 2003;Levine et al 2006) or molecular clouds (Grabelsky et al 1987;Wouterloot et al 1990;May et al 1997). Recent analysis of the outer Galaxy either from 2MASS (López-Corredoira et al 2002;Momany et al 2006;Reylé et al 2009) or from SDSS (Hammersley & López-Corredoira 2011) has led to the conclusion that even the stars follow a warped structure. However, it has not been clearly established that the shape of the warp is similar or deviates from the gas structure.…”

Section: Introductionmentioning

confidence: 99%

Evolution over time of the Milky Way’s disc shape

Amôres

Robin

Reylé

2017

A&A

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Context. Galactic structure studies can be used as a path to constrain the scenario of formation and evolution of our Galaxy. The dependence with the age of stellar population parameters would be linked with the history of star formation and dynamical evolution. Aims. We aim to investigate the structures of the outer Galaxy, such as the scale length, disc truncation, warp and flare of the thin disc and study their dependence with age by using 2MASS data and a population synthesis model (the so-called Besançon Galaxy Model). Methods. We have used a genetic algorithm to adjust the parameters on the observed colour-magnitude diagrams at longitudes 80 • ≤ ≤ 280 • for |b| ≤ 5.5 • . We explored parameter degeneracies and uncertainties. Results. We identify a clear dependence of the thin disc scale length, warp and flare shapes with age. The scale length is found to vary between 3.8 kpc for the youngest to about 2 kpc for the oldest. The warp shows a complex structure, clearly asymmetrical with a node angle changing with age from approximately 165 • for old stars to 195 • for young stars. The outer disc is also flaring with a scale height that varies by a factor of two between the solar neighbourhood and a Galactocentric distance of 12 kpc. Conclusions. We conclude that the thin disc scale length is in good agreement with the inside-out formation scenario and that the outer disc is not in dynamical equilibrium. The warp deformation with time may provide some clues to its origin.

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“…To verify this, we made independent A V estimates using a method based on the red-clump stars as standard candles, which provides an A V -distance relation for a given position on the sky (see e.g. López-Corredoira et al 2002). We extracted stars located within 0.3 • of the pulsar position from the 2MASS All-Sky Point Source Catalogue 11 , and created a colour-magnitude diagram, K vs. J − K. We found mean J − K colours of the red-clump branch in several magnitude bins and transformed them to the A V -distance relation, as has been done by Danilenko et al (2012) for another γ-ray pulsar J1357−6429.…”

Section: The Interstellar Extinctionmentioning

confidence: 99%

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

Danilenko¹,

Kirichenko

Sollerman

et al. 2013

A&A

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Context. PSR J1048-5832 is a young radio-pulsar that has recently been detected in γ-rays with Fermi, and also in X-rays with Chandra and XMM-Newton. It powers a compact pulsar wind nebula visible in X-rays and is in many ways similar to the Vela pulsar. Aims. We present deep optical observations made with the ESO Very Large Telescope to search for optical counterparts of the pulsar and its nebula and to explore their multi-wavelength emission properties. Methods. The data were obtained in the V and R bands and were compared with archival data in other spectral domains. Results. We do not detect the pulsar in the optical and derive informative upper limits of R 28. m 1 and V 28. m 4 for its brightness. Using a red-clump star method, we estimate an interstellar extinction towards the pulsar of A V ≈ 2 mag, which is consistent with the absorbing column density derived from X-rays. The respective distance agrees with the dispersion measure distance. We reanalysed the Chandra X-ray data and compared the dereddened upper limits with the unabsorbed X-ray spectrum of the pulsar. We find that regarding its optical-X-ray spectral properties this γ-ray pulsar is not distinct from other pulsars detected in both ranges. However, like the Vela pulsar, it is very inefficient in the optical and X-rays. Among a dozen optical sources overlapping with the pulsar X-ray nebula we find one with V ≈ 26. m 9 and R ≈ 26. m 3, whose colour is slightly bluer than that of the field stars and is consistent with the peculiar colours typical for pulsar nebula features. It positionally coincides with a relatively bright feature of the pulsar X-ray nebula, resembling the Crab wisp and is located in ∼2 from the pulsar. We suggest this source as a counterpart candidate to the feature. Conclusions. Based on the substantial interstellar extinction towards the pulsar and its optical inefficiency, additional optical studies should be carried out at longer wavelengths.

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Old stellar Galactic disc in near-plane regions according to 2MASS: Scales, cut-off, flare and warp

Cited by 269 publications

References 37 publications

The long bar as seen by the VVV Survey

The long bar as seen by the VVV Survey

Evolution over time of the Milky Way’s disc shape

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

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