Results 21 to 30 of about 5,019,889 (353)

Cepheids as Distance Indicators

Annual Review of Astronomy and Astrophysics, 1999
This review attempts to summarize the various ways of determining Cepheid reddenings and luminosities and the zero points of the Cepheid period-luminosity and period-luminosity-color relations. The methods of determining luminosities that are discussed involve Cepheid parallaxes, Cepheid proper motions and radial velocities, Cepheids in clusters and ...
M. Feast
semanticscholar   +2 more sources

Astrophysical Distance Scale. VII. A Self-consistent, Multiwavelength Calibration of the Slopes and Relative Zero Points for the Run of Luminosity with the Color of Stars Defining the Tip of the Red Giant Branch

The Astronomical Journal, 2023
Given the recent successful launch of the James Webb Space Telescope, determining robust calibrations of the slopes and absolute magnitudes of the near- to mid-infrared tip of the red-giant branch (TRGB) will be essential to measuring precise ...
Barry F. Madore, Wendy L. Freedman, Kayla Owens   +2 more
doaj   +1 more source

NOVAE AS DISTANCE INDICATORS.

Publications of the Astronomical Society of the Pacific, 1986
From published photographic observations the dispersion in the maximum magnitude versus rate of decline relation for novae in M31 is σ = 0.28 mag, from which the intrinsic dispersion is found to be σ0 < 0.14 mag. This is far smaller than the 1.5 mag range in distance moduli that corresponds to 50 < H < 100 km s-1Mpc-1.
S. van den Bergh, C. Pritchet
semanticscholar   +2 more sources

Quantifying Uncertainties on the Tip of the Red Giant Branch Method

The Astronomical Journal, 2023
We present an extensive grid of numerical simulations quantifying the uncertainties in measurements of the tip of the red giant branch (TRGB). These simulations incorporate a luminosity function composed of 2 mag of red giant branch (RGB) stars leading ...
Barry F. Madore, Wendy L. Freedman, Kayla A. Owens, In Sung Jang   +3 more
doaj   +1 more source

Multi-level analyses of distance education capacity, faculty members’ adaptation, and indicators of student satisfaction in higher education during COVID-19 pandemic

International Journal of Educational Technology in Higher Education, 2021
COVID-19 pandemic triggered distance education in higher education. Decisions such as isolation, social distancing and quarantine made by countries unexpectedly and suddenly forced face-to-face education to change to distance education within days.
Engin Karadağ, Ahmet Su, Hatice Ergin-Kocaturk   +2 more
semanticscholar   +1 more source

Drift Distance in Aircraft Glyphosate Application Using Rice Plants as Indicators [PDF]

Planta Daninha, 2020
: This study aimed to evaluate the potential for glyphosate drift during aerial application using rice plants as sentinels, aiming to determine the effect of drift on irrigated rice crops.
R.A. CÓRDOVA, M. TOMAZETTI, J.P. REFATTI, D. AGOSTINETTO, L.A. AVILA, E.R. CAMARGO   +5 more
doaj   +1 more source

Coordinated JWST Imaging of Three Distance Indicators in a Supernova Host Galaxy and an Estimate of the Tip of the Red Giant Branch Color Dependence [PDF]

Astrophysical Journal
Boasting a 6.5 m mirror in space, JWST can increase by several times the number of supernovae (SNe) to which a redshift-independent distance has been measured with a precision distance indicator (e.g., tip of the red giant branch (TRGB) or Cepheids); the
Taylor J. Hoyt, In Sung Jang, W. Freedman, B. Madore, Abigail J. Lee, Kayla A. Owens   +5 more
semanticscholar   +1 more source

Cepheids as distance indicators and stellar tracers [PDF]

The Astronomy and Astrophysics Review
We review the phenomenology of classical Cepheids (CCs), Anomalous Cepheids (ACs) and type II Cepheids (TIICs) in the Milky Way (MW) and in the Magellanic Clouds (MCs). We also examine the Hertzsprung progression in different stellar systems by using the
G. Bono, V. Braga, A. P. D. D. Fisica, Universita' di Roma Tor Vergata, Roma, Italy, I. Roma, M. Catone, I. A. d'Abruzzo, Teramo   +9 more
semanticscholar   +1 more source

THE CARNEGIE-CHICAGO HUBBLE PROGRAM. I. AN INDEPENDENT APPROACH TO THE EXTRAGALACTIC DISTANCE SCALE USING ONLY POPULATION II DISTANCE INDICATORS [PDF]

, 2016
We present an overview of the Carnegie-Chicago Hubble Program, an ongoing program to obtain a 3% measurement of the Hubble constant (H0) using alternative methods to the traditional Cepheid distance scale.
R. Beaton, W. Freedman, B. Madore, G. Bono, E. Carlson, G. Clementini, M. Durbin, A. Garofalo, D. Hatt, I. Jang, J. Kollmeier, M. Lee, A. Monson, J. Rich, V. Scowcroft, M. Seibert, L. Sturch, Soung-Chul Yang   +17 more
semanticscholar   +1 more source

HST observations of the LMC field around SN87A: distance determinations with Red Clump and Tip of the Red Giant Branch stars [PDF]

, 1999
We have used HST-WFPC2 multiband observations of a field around SN 1987A in the Large Magellanic Cloud to measure its distance from the Sun. The observations allowed us to carefully determine the interstellar extinction along the line of sight to a large
Bessel M. S., Brocato E., Cassisi S., Feast M. W., M. Romaniello, M. Salaris, N. Panagia, S. Cassisi, Salaris M., Udalski A., Vallenari A.   +10 more
core   +2 more sources