GALEX absolute calibration and extinction coefficients based on white dwarfs

Wall, Renae E.; Kilic, Mukremin; Bergeron, P.; Rolland, B.; Genest-Beaulieu, C.; Gianninas, A.

doi:10.1093/mnras/stz2506

Cited by 20 publications

(12 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…DA white dwarfs are useful spectrophotometric calibrators because their spectra are more or less blackbodies imprinted with broad, deep hydrogen Balmer absorption, making their spectra comparatively easy to model accurately and robustly. It is typically their modeled spectra-not their observed spectrathat are used as the spectrophotometric standards (Holberg 2007;Betoule et al 2013;Axelrod & Miller 2014;Camarota & Holberg 2014;Narayan et al 2016;Calamida et al 2019;López-Sanjuan et al 2019;Narayan et al 2019;Wall et al 2019;Gentile Fusillo et al 2020). For our DA sample, modeling was performed using the DA white dwarf models described in Tremblay et al (2011Tremblay et al ( , 2013.…”

Section: Appendix C Absolute Calibrationsmentioning

confidence: 99%

The Dark Energy Survey Data Release 2

Abbott

Adamów

Aguena

et al. 2021

ApJS

172

View full text Add to dashboard Cite

We present the second public data release of the Dark Energy Survey, DES DR2, based on optical/near-infrared imaging by the Dark Energy Camera mounted on the 4 m Blanco telescope at Cerro Tololo Inter-American Observatory in Chile. DES DR2 consists of reduced single-epoch and coadded images, a source catalog derived from coadded images, and associated data products assembled from 6 yr of DES science operations. This release includes data from the DES wide-area survey covering ∼5000 deg 2 of the southern Galactic cap in five broad photometric bands, grizY. DES DR2 has a median delivered point-spread function FWHM of g = 1.11″, r = 0.95″, i = 0.88″, z = 0.83″, and Y = 0 90, photometric uniformity with a standard deviation of < 3 mmag with respect to Gaia DR2 G band, a photometric accuracy of ∼11 mmag, and a median internal astrometric precision of ∼27 mas. The median coadded catalog depth for a 1 95 diameter aperture at signal-to-noise ratio = 10 is g = 24.7, r = 24.4, i = 23.8, z = 23.1, and Y = 21.7 mag. DES DR2 includes ∼691 million distinct astronomical objects detected in 10,169 coadded image tiles of size 0.534 deg 2 produced from 76,217 single-epoch images. After a basic quality selection, benchmark galaxy and stellar samples contain 543 million and 145 million objects, respectively. These data are accessible through several interfaces, including interactive image visualization tools, web-based query clients, image cutout servers, and Jupyter notebooks. DES DR2 constitutes the largest photometric data set to date at the achieved depth and photometric precision.

show abstract

Section: Appendix C Absolute Calibrationsmentioning

confidence: 99%

The Dark Energy Survey Data Release 2

Abbott

Adamów

Aguena

et al. 2021

ApJS

172

View full text Add to dashboard Cite

show abstract

“…While we were able to achieve an adequate fit to these photometry, we found the resulting model (T eff = 12,400 K) proved inconsistent with the Balmer lines in our optical spectroscopy. Suspecting poor absolute calibration of the Galex fluxes 37 , we acquired NUV SWIFT photometry in December 2018. These observations were performed with the U, UVW1, and UVW2 filters using the UVOT (Ultraviolet/Optical Telescope) instrument.…”

Section: Spectroscopic Observations and Reductionsmentioning

confidence: 99%

An ultra-massive white dwarf with a mixed hydrogen–carbon atmosphere as a likely merger remnant

et al. 2020

View full text Add to dashboard Cite

White dwarfs are dense, cooling stellar embers consisting mostly of carbon and oxygen 1 , or oxygen and neon (with a few percent carbon) at higher initial stellar masses 2 . These stellar cores are enveloped by a shell of helium which in turn is usually surrounded by a layer of hydrogen, generally prohibiting direct observation of the interior composition. However, 1 arXiv:2003.00028v1 [astro-ph.SR] 28 Feb 2020 carbon is observed at the surface of a sizeable fraction of white dwarfs 3, 4 , sometimes with traces of oxygen, and it is thought to be dredged-up from the core by a deep helium convection zone 5, 6 . In these objects only traces of hydrogen are found 7, 8 as large masses of hydrogen are predicted to inhibit hydrogen/helium convective mixing within the envelope 9 . We report the identification of WD J055134.612+413531.09, an ultra-massive (1.14 M ) white dwarf with a unique hydrogen/carbon mixed atmosphere (C/H = 0.15 in number ratio). Our analysis of the envelope and interior indicates that the total hydrogen and helium mass fractions must be several orders of magnitude lower than predictions of single star evolution 10 : less than 10 −9.5 and 10 −7.0 , respectively. Due to the fast kinematics (129 ± 5 km s −1 relative to the local standard of rest), large mass, and peculiar envelope composition, we argue that WD J0551+4135 is consistent with formation from the merger of two white dwarfs in a tight binary system [11][12][13][14] .WD J0551+4135 was identified as a candidate high-mass white dwarf 15 from its location in the Gaia Hertzsprung-Russell diagram 16 (Fig. 1). The Gaia parallax places WD J0551+4135 at 46.45 ± 0.15 pc away from the Sun. Compared to most other white dwarfs of the same G BP − G RP colour, WD J0551+4135 is fainter in absolute magnitude, signifying a relatively small radius, and thus a large mass given the mass-radius relation of white dwarfs whose structure is dominated by electron degeneracy 17 .− log(1 − m r /M wd ) = 4 (where m r is the mass enclosed within a sphere of radius r), the models are almost indistinguishable. Therefore the degree of oxygen dredge-up is not found to depend upon the core-composition, and so the atmospheric non-detection of oxygen cannot be used to test the evolutionary history. 6

show abstract

“…We estimate the SFR using the FUV magnitude (20.62 mag AB) from the GALEX catalog. The magnitude is corrected for dust extinction assuming R 𝐹𝑈 𝑉 = 8.01 (Wall et al 2019) and E(B-V)=0.09 in the direction of UGC 12591 obtained from IPAC dust maps. The corrected FUV magnitude of UGC 12591 thus estimates is (19.85 mag AB) corresponding to F 𝜆 =5.42 × 10 −16 ergs s −1 cm −2 Å −1 (F 𝜈 = 4.22 × 10 −28 ergs s −1 cm −2 Hz −1 ) and luminosity L FUV =4.66 × 10 26 ergs s −1 Hz −1 .…”

Section: Fuv Derived Star Formation Ratementioning

confidence: 99%

Hubble Space Telescope Captures UGC 12591: Bulge/Disk Properties, Star Formation and `Missing Baryons' Census in a Very Massive and Fast Spinning Hybrid Galaxy

Ray¹,

Dhiwar²,

Pandge³

et al. 2022

Preprint

View full text Add to dashboard Cite

We present Hubble Space Telescope (HST) observations of the nearby (z= 0.023), very massive, highly rotating (488.4±12.5 km s −1 ) hybrid (S0-Sa) galaxy UGC 12591, along with observations taken at other wavelengths from UV to FIR. Deep HST data of the galaxy in V, I and H bands is used to disentangle its bulge and disk components. The surface brightness distributions show a dominance of the bulge component over the disk with H-band bulge-to-disc luminosity ratio ∼ 69%. From spectral energy distribution (SED) fitting, we find an extremely low global star formation rate (SFR) of ∼ 0.1 − 0.2M y −1 , which is unusually low for this galaxy's huge stellar mass (M ★ ∼ 1.6 × 10 11 M ), that implies a strong quenching of it's SFR. For at least past 10 8 years the galaxy has remained in the quiescent state as a sterile, 'red and dead' galaxy. The fraction of total infra-red dust luminosity contributed by the ISM dust is as high as ∼ 90%, with total dust luminosity L dust = (0.5 − 3.5) × 10 10 L , dominated by cold dust at equilibrium temperature T C ≈ 15K. UGC 12591 is found host to a super massive black hole (SMBH) of mass 6.18 × 10 8 M which at the present moment is quiescent, i.e., neither we see large (> 1kpc) radio jets nor is the black hole contributing significantly to the mid-IR SED, ruling out the presence of strong radiative feedback from a bright AGN. We have obtained a detailed census of all observable baryons in this galaxy. The star formation efficiency is very low (∼ 0.02 − 0.06) and within a virial radius the galaxy has a total observed baryonic mass of 6.87 × 10 11 M , amounting to a baryonic deficiency of ∼ 80% relative to the cosmological mean. A small fraction of these cosmic baryons reside in a warm/hot circum-galactic halo phase, while the majority of baryons are still not observable. We have discussed various astrophysical scenarios for explaining its unusual physical properties. Our work is a major step forward in understanding the assembly history of such extremely massive, isolated galaxies.

show abstract

GALEX absolute calibration and extinction coefficients based on white dwarfs

Cited by 20 publications

References 34 publications

The Dark Energy Survey Data Release 2

The Dark Energy Survey Data Release 2

An ultra-massive white dwarf with a mixed hydrogen–carbon atmosphere as a likely merger remnant

Hubble Space Telescope Captures UGC 12591: Bulge/Disk Properties, Star Formation and `Missing Baryons' Census in a Very Massive and Fast Spinning Hybrid Galaxy

Contact Info

Product

Resources

About