J/ApJ/900/9 AMIGA: The Circumgalactic Medium of Andromeda (Lehner+, 2020)
Project AMIGA: The Circumgalactic Medium of Andromeda.
Lehner N., Berek S.C., Howk J.C., Wakker B.P., Tumlinson J., Jenkins E.B.,
Prochaska J.X., Augustin R., Ji S., Faucher-Giguere C.-A., Hafen Z.,
Peeples M.S., Barger K.A., Berg M.A., Bordoloi R., Brown T.M., Fox A.J.,
Gilbert K.M., Guhathakurta P., Kalirai J.S., Lockman F.J., O'Meara J.M.,
Pisano D.J., Ribaudo J., Werk J.K.
<Astrophys. J., 900, 9 (2020)>
=2020ApJ...900....9L 2020ApJ...900....9L
ADC_Keywords: QSOs; Galaxies; Interstellar medium; Spectra, ultraviolet;
Spectra, infrared; Redshifts; Abundances
Keywords: Circumgalactic medium ; Andromeda Galaxy ; Local Group ;
Quasar absorption line spectroscopy
Abstract:
Project AMIGA (Absorption Maps In the Gas of Andromeda) is a survey of
the circumgalactic medium (CGM) of Andromeda (M31, Rvir∼300kpc)
along 43 QSO sightlines at impact parameters 25≲R≲569kpc (25 at
R≲Rvir). We use ultraviolet absorption measurements of SiII, SiIII,
SiIV, CII, and CIV from the Hubble Space Telescope/Cosmic Origins
Spectrograph and OVI from the Far Ultraviolet Spectroscopic Explorer
to provide an unparalleled look at how the physical conditions and
metals are distributed in the CGM of M31. We find that SiIII and OVI
have a covering factor near unity for R≲1.2Rvir and ≲1.9Rvir,
respectively, demonstrating that M31 has a very extended ∼104-105.5K
ionized CGM. The metal and baryon masses of the 104-105.5K CGM gas
within Rvir are ≳108 and ≳4x1010 (Z/0.3Z☉)-1M☉,
respectively. There is not much azimuthal variation in the column
densities or kinematics, but there is with R. The CGM gas at
R≲0.5Rvir is more dynamic and has more complicated, multiphase
structures than at larger radii, perhaps a result of more direct
impact of galactic feedback in the inner regions of the CGM. Several
absorbers are projected spatially and kinematically close to M31 dwarf
satellites, but we show that those are unlikely to give rise to the
observed absorption. Cosmological zoom simulations of ∼L* galaxies
have OVI extending well beyond Rvir as observed for M31 but do not
reproduce well the radial column density profiles of the lower ions.
However, some similar trends are also observed, such as the lower ions
showing a larger dispersion in column density and stronger dependence
on R than higher ions. Based on our findings, it is likely that the
Milky Way has a ∼104-105.5K CGM as extended as for M31 and their CGM
(especially the warm-hot gas probed by OVI) are overlapping.
Description:
With Project Absorption Maps In the Gas of Andromeda (AMIGA), we have
surveyed the circumgalactic medium (CGM) of a single galaxy (M31) with
an unprecedented number of background targets (43). The 43 QSOs were
all observed with Hubble Space Telescope/Cosmic Origins Spectrograph
(HST/COS) G130M/G160M or G130M (providing in particular OI, CII, CIV,
SiII, SiIII, and SiIV), and 11 were also observed with Far Ultraviolet
Spectroscopic Explorer (FUSE) (providing OVI). The resolution of the
COS G130M/G160M and the S/Ns have been key for the success of this
program.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 100 43 Sample summary
table2.dat 79 903 Summary of the results
table3.dat 87 32 Summary of the M31 dwarf galaxies
table4.dat 50 58 QSO absorbers within R200 of M31 dwarf galaxies
tablea1.dat 92 5642 Line list identification
tabled1.dat 59 111 Summary of the profile fit results
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See also:
VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+, 2005)
J/ApJS/136/463 : Distances and metallicities of HVCs and IVCs (Wakker, 2001)
J/ApJS/146/1 : O VI absorption in FUSE survey (Wakker+, 2003)
J/AJ/127/2738 : ACS VI photometry of M31 halo RR Lyrea (Brown+, 2004)
J/ApJS/163/282 : Molecular hydrogen column densities (Wakker+, 2006)
J/ApJS/168/213 : Ionization states and cooling efficiencies (Gnat+, 2007)
J/ApJS/177/39 : Survey of low-redshift OVI absorbers (Tripp+, 2008)
J/ApJ/700/1299 : Gas-phase element depletions in the ISM (Jenkins, 2009)
J/ApJ/703/614 : UV star-forming regions in M31 (Kang+, 2009)
J/ApJS/187/388 : A XMM-Newton survey of the SXRB (Henley+, 2010)
J/ApJ/727/46 : Highly ionized plasmas in the Milky Way (Lehner+, 2011)
J/AJ/144/4 : Prop. of dwarf galaxies in Local Group (McConnachie+, 2012)
J/ApJ/745/156 : M31 Cepheids with HST/WFC3 (Riess+, 2012)
J/ApJ/768/172 : Kinematic analysis of red giant in M31 dSphs (Collins+, 2013)
J/ApJ/770/138 : Metallicities of Lyman limit systems and DLA (Lehner+, 2013)
J/ApJ/788/119 : Properties of the highly ionized gas of quasars (Lehner+,2014)
J/MNRAS/445/2061 : Absorption in multiphase circumgalactic medium (Liang+,2014)
J/MNRAS/449/3263 : Extended galaxy halo gas through HI and OVI (Johnson+, 2015)
J/ApJ/804/79 : HST/COS obs. of QSOs within 600kpc of M31 (Lehner+, 2015)
J/ApJ/814/40 : Nearby galaxy filaments with UV obs. (Wakker+, 2015)
J/ApJ/833/167 : PAndAS view of Andromeda satellites. II. (Martin+, 2016)
J/AJ/154/41 : Rotational velocities of M33 (Kam+, 2017)
J/ApJS/230/6 : HST-COS & -STIS absorption-line spectroscopy II (Keeney+,2017)
J/A+A/607/A48 : AGN data and absorption-line measurements (Richter+, 2017)
J/ApJ/846/145 : PHAT. XIX. Formation history of M31 disk (Williams+, 2017)
J/ApJ/866/33 : The COS CGM compendium. I. Initial results (Lehner+, 2018)
J/ApJ/887/5 : COS CGM compendium. III. z≤1Lyα syst. (Lehner+, 2019)
J/ApJ/872/81 : The COS CGM Compendium. II. Lyman limit syst. (Wotta+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- QSO QSO name
25- 29 F5.3 --- z [0.01/0.86] QSO redshift
31- 37 F7.3 deg RAdeg [0.24/358] Right Ascension (J2000)
39- 44 F6.3 deg DEdeg [-1.16/46] Declination (J2000)
46- 51 F6.1 deg LON [-131.7/-76.9] Longitude, Magellanic Stream (1)
53- 57 F5.1 deg LAT [-13.9/46.7] Latitude, Magellanic Stream (1)
59- 63 F5.1 kpc Rad [25/568.7] Radial projected distance (2)
65- 70 F6.1 kpc X [-462.4/397.6] Cartesian X projected distance (2)
72- 77 F6.1 kpc Y [-534/57.9] Cartesian Y projected distance (2)
79- 83 I5 --- PID [11524/14268] HST Program identifier (3)
85- 95 A11 --- COS COS Grating used
97-100 F4.1 --- S/N [3.4/32.7] Signal-to-noise ratio (4)
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Note (1): See Nidever+, 2008ApJ...679..432N 2008ApJ...679..432N for the definition of the
Magellanic Stream coordinate system.
Note (2): All the projected distances are computed using the three
dimensional separation with coordinates of the target and distance of
M31 assumed to be 752 kpc.
Note (3): The 18 sightlines from our large HST program have the PID 14268;
for the supplemental archival 25 other targets, the HST PID is listed.
Note (4): The SNR is given per COS resolution element (assuming R∼17,000)
and estimated in the continuum near Si III λ1206.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- QSO QSO name
25- 30 A6 --- Ion Atomic/Ionic Species
32- 37 F6.1 km/s b_Vel [-535/-190] lower velocity bound (1)
39- 44 F6.1 km/s B_Vel [-485/-120] upper velocity bound (1)
46- 51 F6.1 km/s Vel [-507.6/-152.6]? average velocity
53- 57 F5.1 km/s e_Vel [0.4/177]? Uncertainty in Vel
59- 63 F5.2 [/cm2] logN [11.53/15.58] log, column density
65- 68 F4.2 [/cm2] E_logN [0.01/0.19] Upper uncertainty in logN
70- 73 F4.2 [/cm2] e_logN [0.01/0.34] Lower uncertainty in logN
75- 76 I2 --- f_logN [-2/0] Line detection flag (2)
78- 79 I2 --- MS [-1/0] Magellanic Stream contamination flag (3)
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Note (1): The velocities v1 and v2 correspond to the boundaries of the
integration of the absorption component.
Note (2): Flags as follows:
0 = detection (not saturated or contaminated; 232 occurrences)
-1 = upper limit (621 occurrences)
-2 = lower limit (due to saturation of the line; 50 occurrences)
Note (3): Flags as follows:
0 = not contaminated by the MS (607 occurrences)
-1 = contaminated by the MS (296 occurrences)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Dwarf Galaxy name
11- 19 A9 --- Type Dwarf Galaxy type
21- 26 F6.1 deg LON [-147/-105] Longitude, Magellanic Stream (1)
28- 31 F4.1 deg LAT [4.6/49.4] Latitude, Magellanic Stream (1)
33- 38 F6.1 km/s Vel [-535/-101] Velocity relative to the local
standard of rest
40- 44 F5.1 kpc Dist [600/933] Absolute distance to dwarf galaxy
46- 50 F5.1 kpc Rad [5.3/337.5] Radial projected distance (2)
52- 57 F6.1 kpc X [-252.4/331.3] Cartesian X projected distance (2)
59- 64 F6.1 kpc Y [-251.4/237.1] Cartesian Y projected distance (2)
66- 71 F6.1 10+5Msun Mass [0.3/3300.0] Total stellar mass (3)
73- 77 F5.1 10+8Msun M200 [9.8/864.8] Virial mass (3)
79- 82 F4.1 kpc R200 [20.9/93.2] Virial radius (3)
84- 87 F4.1 km/s v200 [20.0/89.3] Circular velocity (3)
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Note (1): See Nidever+, 2008ApJ...679..432N 2008ApJ...679..432N for the definition of
the Magellanic Stream coordinate system.
Note (2): All the projected distances are computed using the three
dimensional separation with coordinates of the target and distance of
M31 assumed to be 752kpc.
Note (3): Galaxy parameters are from McConnachie+, 2012, J/AJ/144/4,
Martin+, 2014ApJ...793L..14M 2014ApJ...793L..14M, 2016, J/ApJ/833/167) and references therein.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Dwarf Galaxy name (1)
11- 26 A16 --- QSO QSO name (1)
28- 33 F6.1 km/s vLSR [-639/-459] velocity, LSR, from SiIII absorption at
M∼31
35- 38 F4.2 kpc dSep [0.17/0.99] projected separation
40- 44 F5.1 km/s vesc [28.5/187.3] escape velocity (2)
46- 50 F5.1 km/s dv [1.2/367.3] velocity separation (3)
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Note (1): The match between dwarfs and QSO absorbers was made so that the
projected separation between the dwarf and QSO is within R200 of the
dwarf, i.e., dSep=r/Rdwarf,200≤1 (where r is the projected distance
between the QSO and dwarf).
Note (2): Escape velocity of the dwarf at the projected distance of the
QSO assuming a point-like mass with halo mass listed in Table 3
Note (3): The velocity separation between the QSO absorber and the dwarf is
dv =|νM31,SiIII-νM31,dwarf|.
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- QSO QSO name
25- 31 F7.2 0.1nm lambda [905/2853] Observed wavelength
33- 44 A12 --- Type Absorption type (1)
46- 51 A6 --- Ion Atomic/Ionic Species
53- 58 F6.1 0.1nm Rest [763/2853]?=0.0 Wavelength of Ion in Frame
60- 60 A1 --- Frame Reference frame (2)
62- 69 A8 km/s Vel Velocity
71- 78 F8.5 --- z [-1/0.83] Redshift
80- 86 F7.1 10-13m EW [-3715/8206] Equivalent Width
88- 92 F5.1 10-13m e_EW [0.1/306]?=0.0 Uncertainty in EWl (3)
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Note (1): Types as follows:
IGMABS = intervening IGM/CGM absorber at dv>3000 km/s from the QSO redshift
ISMLG = any ISM/CGM/IGM absorption from the Local Group environment
PROXIMATE = proximate/associated absorber at 500<dv<3000km/ from he QSO z
INTRINSIC = intrinsic absorber at dv<500km/s from the QSO redshift
UNIDENTIFIED = unknown origin of the absorption
OTHER = FPN: fixed-pattern noise feature
EDGE: special case of fixed-pattern noise feature occurring
near the edge of the COS detector
FLAW: refers to the 1043 Angstrom detector flaw in the FUSE data
that causes a fake line.
Note (2): Frames as follows:
L = LSR frame (any absorption at |vLSR|≤500)
H = heliocentric frame (any absorption at |vLSR|>500)
Note (3): Note that the equivalent widths (EW) and errors are provided for
guidelines and should not be used for quantitative scientific purposes.
The H_2 lines are not individually measured, but are based on a model of
the H_2 absorption, which is the reason for not providing an error on EWl
(i.e., in the table it is set to a null, i.e., "0.0").
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Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- QSO QSO name
17- 22 A6 --- Ion Atomic/Ionic Species
24- 24 I1 --- Comp [1/6] Component number
26- 31 F6.1 km/s Vel [-471.4/57.2] velocity component
33- 36 F4.1 km/s e_Vel [0.5/36.2] Uncertainty (1σ) in v
38- 41 F4.1 km/s b [1.6/99] Doppler parameter
43- 47 F5.1 km/s e_b [0.8/999] Uncertainty (1σ) in b
49- 53 F5.2 [/cm2] logN [12.29/14.7] log, column density
55- 59 F5.2 [/cm2] e_logN [0.01/24.7] Uncertainty (1σ) in logN
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 27-Oct-2021