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Interstellar extinction of classical Cepheids from neighboring stars I. Methodology and application to 16 Galactic Cepheids
Wilma Kiviaho, Pierre Kervella, Mika Juvela +21
Galactic Cepheid variable stars are fundamental calibrators of the cosmic distance scale through their Period-Luminosity (PL) relation. The high-precision parallaxes expected from…
HALO II: Constraining Hubble constant through continuum delay fitting of Fairall 9
Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal +28
The Hubble tension remains one of the most significant unresolved problems in modern cosmology. A key question is whether it may arise from underestimated systematic uncertainties…
Reddening maps of the Magellanic Clouds using spectral energy distribution fitting of red giants
H. Netzel, G. Pietrzyński, M. Górski +9
Robust reddening maps of the Large and Small Magellanic Clouds (LMC/SMC) are crucial for a wide range of astrophysical studies, including the calibration of the cosmic distance lad…
HALO I: Photometric continuum reverberation mapping of Fairall 9
Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal +23
We investigate the origin of inter-band continuum time delays in active galactic nuclei (AGNs) to study the structure and properties of their accretion disks. We aim to measure the…
Period-Luminosity Relations for Galactic classical Cepheids in the Sloan bands
Weronika Narloch, Gergely Hajdu, Grzegorz Pietrzynski +6
We present the first period-luminosity (PL) and period-Wesenheit (PW) relations in the Sloan-Pans-STARRS gP1rP1iP1 bands for classical fundamental mode Cepheids in the Milky Way. W…
Wavelength-resolved reverberation mapping of intermediate redshift quasars HE 0413-4031 and HE 0435-4312: Dissecting Mg II, optical Fe II, and UV Fe II emission regions
Raj Prince, Michal Zajaček, S. Panda +24
We present the wavelength-resolved reverberation mapping (RM) of combined MgII and UV FeII broad-line emissions for two intermediate redshifts (z1), luminous quasars - HE 041…
Synthetic Population of Binary Cepheids. II. The effect of companion light on the extragalactic distance scale
Paulina Karczmarek, Gergely Hajdu, Grzegorz Pietrzyński +5
Because of their period-luminosity relation (PLR), classical Cepheids play a key role in the calibration of the extragalactic distance scale and the determination of the Hubble-Lem…
Metallicities and ages for star clusters and their surrounding fields in the Large Magellanic Cloud
W. Narloch, G. Pietrzyński, W. Gieren +15
We study 147 star clusters in the Large Magellanic Cloud (LMC) in order to determine their mean metallicities and ages, as well as the mean metallicities of 80 surrounding fields.…
The Araucaria Project. Distances to Nine Galaxies Based on a Statistical Analysis of their Carbon Stars (JAGB Method)
Bartłomiej Zgirski, Grzegorz Pietrzyński, Wolfgang Gieren +13
Our work presents an independent calibration of the J-region Asymptotic Giant Branch (JAGB) method using Infrared Survey Facility (IRSF) photometric data and a custom luminosity fu…
The influence of metallicity on the Leavitt Law from geometrical distances of Milky Way and Magellanic Clouds Cepheids
Louise Breuval, Pierre Kervella, Piotr Wielgórski +7
The Cepheid Period-Luminosity (PL) relation is the key tool for measuring astronomical distances and for establishing the extragalactic distance scale. In particular, the local val…
Inspecting the Cepheid distance ladder: The Hubble Space Telescope distance to the SNIa host galaxy NGC 5584
Behnam Javanmardi, Antoine Mérand, Pierre Kervella +7
The current tension between the direct and the early Universe measurements of the Hubble Constant, , requires detailed scrutiny of all the data and methods used in the studies…
The Araucaria Project: Deep near-infrared photometric maps of Local and Sculptor Group galaxies. I. Carina, Fornax, Sculptor
Paulina Karczmarek, Grzegorz Pietrzyński, Wolfgang Gieren +12
Deep near-infrared - and -band photometry of three Local Group dwarf spheroidal galaxies: Fornax, Carina, and Sculptor, is made available for the community. Until now, these…
Metallicities and ages for 35 star clusters and their surrounding fields in the Small Magellanic Cloud
W. Narloch, G. Pietrzyński, W. Gieren +13
In this work we study 35 stellar clusters in the Small Magellanic Cloud (SMC) in order to provide their mean metallicities and ages. We also provide mean metallicities of the field…
Time Delay of MgII Emission Response for the Luminous Quasar HE 0435-4312: Towards Application of High-Accretor Radius-Luminosity Relation in Cosmology
Michal Zajaček, Bożena Czerny, Mary Loli Martinez-Aldama +21
Using the six years of the spectroscopic monitoring of the luminous quasar HE 0435-4312 () with the Southern African Large Telescope (SALT), in combination with the photo…
A distance determination to the Small Magellanic Cloud with an accuracy of better than 2 percent based on late-type eclipsing binary stars
Dariusz Graczyk, Grzegorz Pietrzynski, Ian B. Thompson +17
We present a new study of late-type eclipsing binary stars in the Small Magellanic Cloud (SMC) undertaken with the aim of improving the distance determination to this important gal…
Time-delay measurement of MgII broad line response for the highly-accreting quasar HE 0413-4031: Implications for the MgII-based radius-luminosity relation
Michal Zajaček, Bożena Czerny, Mary Loli Martinez-Aldama +16
We present the monitoring of the AGN continuum and MgII broad line emission for the quasar HE 0413-4031 () based on the six-year monitoring by the South African Large Teles…
Empirical calibration of the reddening maps in the Magellanic Clouds
Marek Gorski, Bartlomiej Zgirski, Grzegorz Pietrzynski +9
We present reddening maps of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), based on color measurements of the red clump. Reddening values of our maps were obta…
Optical continuum photometric reverberation mapping of the Seyfert-1 galaxy Mrk509
F. Pozo Nuñez, N. Gianniotis, J. Blex +6
We present the results of a two year optical continuum photometric reverberation mapping campaign carried out on the nucleus of the Seyfert-1 galaxy Mrk509. Specially designed narr…
A distance to the Large Magellanic Cloud that is precise to one per cent
G. Pietrzynski, D. Graczyk, A. Gallenne +19
In the era of precision cosmology, it is essential to empirically determine the Hubble constant with an accuracy of one per cent or better. At present, the uncertainty on this cons…
Time delay measurement of Mg II line in CTS C30.10 with SALT
Bozena Czerny, Aleksandra Olejak, Mateusz Ralowski +18
We report 6 yr monitoring of a distant bright quasar CTS C30.10 (z = 0.90052) with the Southern African Large Telescope (SALT). We measured the rest-frame time-lag of da…
Metallicity estimates of young clusters in the Magellanic Clouds from Stromgren photometry of supergiant stars
A. E. Piatti, G. Pietrzyński, W. Narloch +2
We present results obtained from Stromgren photometry of 13 young (~30-220 Myr) Magellanic Cloud (MC) clusters, most of them lacking in the literature from direct metallicity measu…
The Araucaria Project. Multi-band calibrations of the TRGB absolute magnitude
Marek Górski, Grzegorz Pietrzyński, Wolfgang Gieren +10
We present new empirical calibrations of the absolute magnitude of the tip of the red giant branch (TRGB) in the optical I and near-infrared J, H, and K bands in terms of the (V-K)…
Quantitative Spectroscopy of Supergiants in the Local Group Dwarf Galaxy IC 1613: Metallicity and Distance
Travis A. Berger, Rolf-Peter Kudritzki, Miguel A. Urbaneja +4
We present the spectral analysis of 21 blue supergiant stars of spectral type late B to early A within the Local Group dwarf galaxy IC 1613 based on VLT-FORS2 low resolution spectr…
SMHASH: Anatomy of the Orphan Stream using RR Lyrae stars
David Hendel, Victoria Scowcroft, Kathryn V. Johnston +30
Stellar tidal streams provide an opportunity to study the motion and structure of the disrupting galaxy as well as the gravitational potential of its host. Streams around the Milky…