A lack of classical Cepheids in the inner part of the Galactic disk

Abstract

Recent large-scale infrared surveys have been revealing stellar populations in the inner Galaxy seen through strong interstellar extinction in the disk. In particular, classical Cepheids with their period-luminosity and period-age relations are useful tracers of Galactic structure and evolution. Interesting groups of Cepheids reported recently include four Cepheids in the Nuclear Stellar Disk (NSD), about 200 pc around the Galactic Centre, found by Matsunaga et al. and those spread across the inner part of the disk reported by Dekany and collaborators. We here report our discovery of nearly thirty classical Cepheids towards the bulge region, some of which are common with Dekany et al., and discuss the large impact of the reddening correction on distance estimates for these objects. Assuming that the four Cepheids in the NSD are located at the distance of the Galactic Centre and that the near-infrared extinction law, i.e. wavelength dependency of the interstellar extinction, is not systematically different between the NSD and other bulge lines-of-sight, most of the other Cepheids presented here are located significantly further than the Galactic Centre. This suggests a lack of Cepheids in the inner 2.5 kpc region of the Galactic disk except the NSD. Recent radio observations show a similar distribution of star-forming regions.

arXiv comment8 pages, 4 figures, accepted for publication in MNRAS

References in corpus (36)

• VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way
• An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
• Reddening and Extinction Toward the Galactic Bulge from OGLE-III: The Inner Milky Way's Rv ~ 2.5 Extinction Curve
• The Nuclear Bulge of the Galaxy. III. Large-Scale Physical Characteristics of Stars and Interstellar Matter
• Mapping the Three-Dimensional Density of the Galactic Bulge with VVV Red Clump Stars
• Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations
• Massive Stars in the Quintuplet Cluster
• Interstellar Extinction Law toward the Galactic Center III: J, H, Ks bands in the 2MASS and the MKO systems, and 3.6, 4.5, 5.8, 8.0 micron in the Spitzer/IRAC system
• Massive Stars in the Arches Cluster
• Line derived infrared extinction towards the Galactic Center
• Interstellar Extinction Law in the J, H, and Ks Bands toward the Galactic Center
• The Green Bank Telescope HII Region Discovery Survey II. The Source Catalog
• Star Formation in the Central 400 pc of the Milky Way: Evidence for a Population of Massive YSOs
• Cepheid Parallaxes and the Hubble Constant
• Classical Cepheid Pulsation Models. X. The Period-Age Relation
• Modelling the Galactic bar using OGLE-II Red Clump Giant Stars
• Mapping the X-Shaped Milky Way Bulge
• A New Spiral Arm of the Galaxy: The Far 3-Kpc Arm
• A Distinct Structure Inside the Galactic Bar
• Characteristics of the Galaxy according to Cepheids
• Three classical Cepheid variable stars in the nuclear bulge of the Milky Way
• A near-infrared survey of Miras and the distance to the Galactic Centre
• Mapping the Milky Way bulge at high resolution: the 3D dust extinction, CO, and X factor maps
• Trigonometric parallaxes to star-forming regions within 4 kpc of the galactic center
• Isolated Wolf-Rayet Stars and O Supergiants in the Galactic Center Region Identified via Paschen-alpha Excess
• The Carnegie Hubble Program: The Leavitt Law at 3.6 and 4.5 micron in the Milky Way
• The Green Bank Telescope HII Region Discovery Survey: III. Kinematic Distances
• Cepheid Variables in the Flared Outer Disk of our Galaxy
• Cepheids and other short-period variables near the Galactic Centre
• The complex, variable near infrared extinction towards the Nuclear Bulge
• Three dimensional interstellar extinction map towards the Galactic Bulge
• The VVV Survey reveals classical Cepheids tracing a young and thin stellar disk across the Galaxy's bulge
• Kinematics of classical Cepheids in the Nuclear Stellar Disk
• Using Galactic Cepheids to verify Gaia parallaxes
• Discovery of a Pair of Classical Cepheids in an Invisible Cluster Beyond the Galactic Bulge
• HI Absorption Toward HII Regions at Small Galactic Longitudes

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• GALACTICNUCLEUS: A high-angular-resolution JHKs imaging survey of the Galactic centre III. Evidence for wavelength dependence of the extinction curve in the near-infrared
• Galactic Bulge Population II Cepheids in the VVV Survey: Period-Luminosity Relations and a Distance to the Galactic Center
• On the optimal calibration of VVV photometry
• Variability of the near-infrared extinction curve towards the Galactic centre
• Near-Infrared Variability Study of the Central 2.3 arcmin x 2.3 arcmin of the Galactic Centre II. Identification of RR Lyrae Stars in the Milky Way Nuclear Star Cluster
• Using classical Cepheids to study the far side of the Milky Way disk: I. Spectroscopic classification and the metallicity gradient
• Into the Darkness: Classical and Type II Cepheids in the Zona Galactica Incognita
• Timing the Milky Way bar formation and the accompanying radial migration episode
• First metallicity determination from Near-Infrared spectra for five obscured Cepheids discovered in the inner Disk
• An extremely low mid-infrared extinction law toward the Galactic Center and 4% distance precision to 55 classical Cepheids
• Impact of distance determinations on Galactic structure. I. Young and intermediate-age tracers
• The extinction law in the inner $3\times 3$ deg${}^2$ of the Milky Way and the red clump absolute magnitude in the inner bar-bulge
• New type II Cepheids from VVV data towards the Galactic center
• The VVV survey: Long-period variable stars I. Photometric catalog of ten VVV/OGLE tiles
• Young and Intermediate-age Distance Indicators
• New classical Cepheids in the inner part of the northern Galactic disk and their kinematics
• The Gaia-ASAS-SN classical Cepheids sample: I. Sample Selection
• Effective temperatures of classical Cepheids from line-depth ratios in the H-band
• Time-Series Surveys and Pulsating Stars: The Near-Infrared Perspective
• Unveiling VVV/WISE Mira variables on the far side of the Galactic disk: Distances, kinematics and a new extinction law
• Interstellar Extinction Law toward the Galactic Center IV: J, H, and Ks Bands from VVV Red Clump Stars
• Magnetic field structure of the Galactic plane from differential analysis of interstellar polarization
• Large-Scale Surveys of Pulsating Stars for Studying Stellar Populations in the Inner Galaxy
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• San Pedro Meeting on Wide Field Variability Surveys: Some Concluding Comments