Zobrazeno 1 - 10
of 280
pro vyhledávání: '"Webb John K"'
Autor:
Lanzetta, Kenneth M., Gromoll, Stefan, Shara, Michael M., Valls-Gabaud, David, Walter, Frederick M., Webb, John K.
We used the Condor Array Telescope to obtain deep imaging observations through luminance broad-band and He II, [O III], He I, H$\alpha$, [N II], and [S II] narrow-band filters of an extended region of the M81 Group spanning $\approx 8 \times 8$ deg$^
Externí odkaz:
http://arxiv.org/abs/2411.06258
Autor:
Lanzetta, Kenneth M., Gromoll, Stefan, Shara, Michael M., Valls-Gabaud, David, Walter, Frederick M., Webb, John K.
We used the Condor Array Telescope to obtain deep imaging observations through the luminance broad-band and He II 468.6 nm, [O III] 500.7 nm, He I 587.5 nm, H$\alpha$, [N II] 658.4 nm, and [S II] 671.6 nm narrow-band filters of an extended region com
Externí odkaz:
http://arxiv.org/abs/2411.06255
Autor:
Shara, Michael M., Lanzetta, Kenneth M., Garland, James T., Valls-Gabaud, David, Gromoll, Stefan, Misiura, Mikita, Walter, Frederick M., Webb, John K., Martin, Barrett
Classical nova eruptions result from thermonuclear-powered runaways in, and ejection of, the hydrogen-rich envelopes of white dwarf stars accreted from their close binary companions. Novae brighten to up to 1,000,000 solar luminosities, and recur tho
Externí odkaz:
http://arxiv.org/abs/2410.12103
Autor:
Webb, John K., Lee, Chung-Chi, Milaković, Dinko, Dougan, Darren, Dzuba, Vladimir A., Flambaum, Victor V.
Detecting or placing upper limits on spacetime variations of fundamental constants requires quantifying every potential source of uncertainty. We continue our previous study into the impact of continuum variations on measurements of the fine structur
Externí odkaz:
http://arxiv.org/abs/2410.00684
Autor:
Lee, Chung-Chi, Webb, John K., Dougan, Darren, Dzuba, Vladimir A., Flambaum, Victor V., Milaković, Dinko
Searches for variations of fundamental constants require a comprehensive understanding of measurement errors. This paper examines a source of error that is usually overlooked: the impact of continuum placement error. We investigate the problem using
Externí odkaz:
http://arxiv.org/abs/2410.01849
Autor:
Milaković, Dinko, Webb, John K., Molaro, Paolo, Lee, Chung-Chi, Jethwa, Prashin, Cupani, Guido, Murphy, Michael T., Welsh, Louise, D'Odorico, Valentina, Cristiani, Stefano, Santos, Ricardo Génova, Martins, Carlos J. A. P., Nunes, Nelson J., Schmidt, Tobias M., Pepe, Francesco A., Osorio, Maria Rosa Zapatero, Alibert, Yann, Hernández, J. I. González, Di Marcantonio, Paolo, Palle, Enric, Santos, Nuno C., Rebolo, Rafael
Chemical evolution models predict a gradual build-up of $^{13}$C in the universe, based on empirical nuclear reaction rates and assumptions on the properties of stellar populations. However, old metal-poor stars within the Galaxy contain more $^{13}$
Externí odkaz:
http://arxiv.org/abs/2407.17953
Autor:
Webb, John K., Lee, Chung-Chi
Searches for spacetime variations of fundamental constants have entered an era of unprecedented precision. New, high quality quasar spectra require increasingly refined analytic methods. In this article, a continuation in a series to establish robust
Externí odkaz:
http://arxiv.org/abs/2401.00887
Autor:
Webb, John K., Lee, Chung-Chi, Milakovic, Dinko, Flambum, Victor V., Dzuba, Vladimir A., Magueijo, Joao
We report unbiased AI measurements of the fine structure constant alpha in two proximate absorption regions in the spectrum of the quasar HE0515-4414. The data are high resolution, high signal to noise, and laser frequency comb calibrated, obtained u
Externí odkaz:
http://arxiv.org/abs/2401.00888
Autor:
Shara, Michael M., Lanzetta, Kenneth M., Garland, James T., Gromoll, Stefan, Valls-Gabaud, David, Walter, Frederick M., Webb, John K., Kniazev, Alexei, Townsend, Lee, Darnley, Matthew J., Healy-Kalesh, Michael, Corral-Santana, Jesus, Schmidtobreick, Linda
Just 10 recurrent novae (RNe) - which erupt repeatedly on timescales shorter than one century - are known in our Galaxy. The most extreme RN known (located in the Andromeda galaxy), M31N 2008-12a, undergoes a nova eruption every year, and is surround
Externí odkaz:
http://arxiv.org/abs/2310.17055
Autor:
Lanzetta, Kenneth M., Gromoll, Stefan, Shara, Michael M., Berg, Stephen, Garland, James, Mancini, Evan, Valls-Gabaud, David, Walter, Frederick M., Webb, John K.
We used the Condor Array Telescope to obtain deep imaging observations through the luminance filter of the entirety of the NGC 5866 Group, including a very extended region surrounding the galaxy NGC 5907 and its stellar stream. We find that the stell
Externí odkaz:
http://arxiv.org/abs/2309.17248