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J/ApJ/836/137      Deep, wide-field g,i imaging of And XXXI      (Rhode+, 2017)

Structural and photometric properties of the Andromeda satellite dwarf galaxy Lacerta I from deep imaging with WIYN pODI. Rhode K.L., Crnojevic D., Sand D.J., Janowiecki S., Young M.D., Spekkens K. <Astrophys. J., 836, 137-137 (2017)> =2017ApJ...836..137R (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Photometry, SDSS Keywords: galaxies: dwarf; galaxies: individual: (Lac I, And XXXI); galaxies: photometry; Local Group Abstract: We present results from WIYN pODI imaging of Lacerta I (And XXXI), a satellite dwarf galaxy discovered in the outskirts of the Andromeda galaxy (M31) in Pan-STARRS1 survey data. Our deep, wide-field g,i photometry reaches ∼3mag fainter than the photometry in the Pan-STARRS1 discovery paper and allows us to trace the stellar population of Lac I beyond two half-light radii from the galaxy center. We measure a Tip of the Red Giant Branch distance for Lac I of (m-M)0=24.44±0.11mag (773±40kpc, or 264±6kpc from M31), which is consistent with the Pan-STARRS1 distance. We use a maximum-likelihood technique to derive structural properties for the galaxy, and find a half-light radius (rh) of 3.24±0.21' (728±47pc), ellipticity (ε) of 0.44±0.03, total magnitude MV=-11.4±0.3, and central surface brightness µV,0=24.8±0.3mag/arcsec2. We find no H I emission in archival data and set a limit on Lac I's neutral gas mass-to-light ratio of MHI/LV<0.06M/L, confirming Lac I as a gas-poor dwarf spheroidal galaxy. Photometric metallicities derived from Red Giant Branch stars within 2 rh yield a median [Fe/H] of -1.68±0.03, which is more metal-rich than the spectroscopically derived value from Martin+ (2014ApJ...793L..14M). Combining our measured magnitude with this higher metallicity estimate places Lac I closer to its expected position on the luminosity-metallicity relation for dwarf galaxies. Description: Observations of Lac I (And XXXI) were obtained on 2013 October 1 with the WIYN 3.5m telescope and the One Degree Imager with a partially filled focal plane (pODI). The mean FWHM of the point-spread function (PSF) in the final combined images is 0.84" in the g-band and 0.70" in the i-band. Objects: ---------------------------------------------------------------- RA (ICRS) DE Designation(s) (Distance) ---------------------------------------------------------------- 22 58 13.2 +41 17 53 Lac I = NAME Lacerta I (D=773kpc) ---------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 58 33577 Photometry of resolved stars in the WIYN pODI images of Lac I (And XXXI)
See also: V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012) J/AJ/144/4 : Dwarf galaxies in the Local Group (McConnachie+, 2012) J/ApJ/756/79 : Optical photom. in 3 Local Group dwarf galaxies (Sand+, 2012) J/ApJ/768/77 : Ultra-compact high velocity clouds from ALFALFA (Adams+, 2013) J/ApJ/779/102 : Metallicities of RGB stars in dwarf galaxies (Kirby+, 2013) J/MNRAS/435/1928 : Dwarf galaxy planes in Local Group (Pawlowski+, 2013) J/A+A/585/A41 : EBHIS spectra and HI column density maps (Winkel+, 2016) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 I5 --- Seq Sequential running number 7- 15 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) 17- 26 F10.6 deg DEdeg Declination in decimal degrees (J2000) 28- 32 F5.2 mag g0mag [13/27] Calibrated, dereddened WIYN/pODI g band magnitude in SDSS system 34- 37 F4.2 mag e_g0mag [0/0.4] Uncertainty (instrumental) in g0mag 39- 42 F4.2 mag Ag [0.3/0.6] Calculated Galactic extinction, g mag 44- 48 F5.2 mag i0mag [13/26.2] Calibrated, dereddened WIYN/pODI i band magnitude in SDSS system 50- 53 F4.2 mag e_i0mag [0/0.4] Uncertainty (instrumental) in i0mag 55- 58 F4.2 mag Ai [0.1/0.3] Calculated Galactic extinction, i mag
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Sep-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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