Thanks to deep optical to near-IR imaging and spectroscopy, significant
progress is made in characterizing the rest-frame UV to optical properties of
galaxies in the early universe (z > 4). Surveys with Hubble, Spitzer, and
ground-based facilities (Keck, Subaru, and VLT) provide spectroscopic and
photometric redshifts, measurements of the spatial structure, stellar masses,
and optical emission lines for large samples of galaxies. Recently, the Atacama
Large (Sub) Millimeter Array (ALMA) has become a major player in pushing
studies of high redshift galaxies to far-infrared wavelengths, hence making
panchromatic surveys over many orders of frequencies possible. While past
studies focused mostly on bright sub-millimeter galaxies, the sensitivity of
ALMA now enables surveys like ALPINE, which focuses on measuring the gas and
dust properties of a large sample of normal main-sequence galaxies at z > 4.
Combining observations across different wavelengths into a single, panchromatic
picture of galaxy formation and evolution is currently and in the future an
important focus of the astronomical community.Comment: 4 pages, 2 figures. Submitted to Proceedings IAU Symposium No. 341,
  201

Bethermin, Matthieu

Capak, Peter

Cassata, Paolo

Faisst, Andreas

LeFevre, Olivier

Schaerer, Daniel

Silverman, John

Yan, Lin

English

arXiv

Thanks to deep optical to near-IR imaging and spectroscopy, significant progress is made in characterizing the rest-frame UV to optical properties of galaxies in the early universe (z > 4. Surveys with Hubble, Spitzer, and ground-based facilities (Keck, Subaru, and VLT) provide spectroscopic and photometric redshifts, measurements of the spatial structure, stellar masses, and optical emission lines for large samples of galaxies. Recently, the Atacama Large (Sub) Millimeter Array (ALMA) has become a major player in pushing studies of high redshift galaxies to far-infrared wavelengths, hence making panchromatic surveys over many orders of frequencies possible. While past studies focused mostly on bright sub-millimeter galaxies, the sensitivity of ALMA now enables surveys like ALPINE, which focuses on measuring the gas and dust properties of a large sample of normal main-sequence galaxies at z > 4. Combining observations across different wavelengths into a single, panchromatic picture of galaxy formation and evolution is currently and in the future an important focus of the astronomical community

Faisst, A.

Béthermin, M.

Capak, P.

Cassata, P.

LeFevre, O.

Schaerer, D.

Silverman, J.

Yan, L.

Caltech Authors - Main

Challenges in Panchromatic Modelling
with Next Generation Facilities
Proceedings IAU Symposium No. 341, 2018
M. Boquien, E. Lusso, C. Gruppioni & P. Tissera
c© 2018 International Astronomical Union
DOI: 00.0000/X000000000000000X
Panchromatic Study of the First Galaxies
with Large ALMA Programs
A. Faisst1, M. Be´thermin2, P. Capak1, P. Cassata3, O. LeFe`vre2, D.
Schaerer4, J. Silverman5, L. Yan1,6, and the ALPINE team
1IPAC, California Institute of Technology,
1200 East California Boulevard, Pasadena, CA 91125, USA
email: afaisst@ipac.caltech.edu
2Laboratoire d’Astrophysique de Marseille
UMR 7326, 13388, Marseille, France
3University of Padova, Department of Physics and Astronomy
Vicolo Osservatorio 3, 35122, Padova, Italy
4Observatoire de Gene`ve, Universite´ de Gene`ve
51 Ch. des Maillettes, 1290 Versoix, Switzerland
5Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo
Kashiwa, Chiba 277-8583, Japan
6Caltech Optical Observatories, Cahill Center for Astronomy and Astrophysics
1200 East California Boulevard, Pasadena, CA 91125, USA
Abstract. Thanks to deep optical to near-IR imaging and spectroscopy, significant progress is
made in characterizing the rest-frame UV to optical properties of galaxies in the early universe
(z > 4). Surveys with Hubble, Spitzer, and ground-based facilities (Keck, Subaru, and VLT)
provide spectroscopic and photometric redshifts, measurements of the spatial structure, stellar
masses, and optical emission lines for large samples of galaxies. Recently, the Atacama Large
(Sub) Millimeter Array (ALMA) has become a major player in pushing studies of high redshift
galaxies to far-infrared wavelengths, hence making panchromatic surveys over many orders of
frequencies possible. While past studies focused mostly on bright sub-millimeter galaxies, the
sensitivity of ALMA now enables surveys like ALPINE, which focuses on measuring the gas
and dust properties of a large sample of normal main-sequence galaxies at z > 4. Combining
observations across different wavelengths into a single, panchromatic picture of galaxy formation
and evolution is currently and in the future an important focus of the astronomical community.
Keywords. Galaxy: formation, Galaxy: evolution, galaxies: ISM, dust, extinction, ISM: evolu-
tion, ISM: kinematics and dynamics, ISM: evolution, infrared: galaxies, surveys
1. Overview
Galaxies evolve significantly over cosmic time in both internal as well as external
properties. The cosmic star formation rate (SFR) density of the early universe increases
rapidly to a redshift z = 2 (Figure 1) and galaxies in the early universe double their stellar
mass at > 10 times faster rates compared to today (Faisst et al. 2016a). This steep mass
growth goes in hand with a significant increase of the dust and metal content (Maiolino
et al. 2008, Bouwens et al. 2009, Faisst et al. 2016b). In addition, star-forming galaxies
evolve from lumpy and turbulent (dominated by gas inflow, mergers, and star-forming
clumps) to smooth disks as cosmic time progresses (Fo¨rster-Schreiber et al. 2009).
In only 500 Myrs between redshifts 4 < z < 6, galaxies significantly increase their
stellar, dust, and gas mass as well as metal content and in addition change their structure
by building up the first stellar disks. Hence, this early growth phase is an important link
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ALPINE
UV 
(Direct Starlight)
ALMA blind surveys
UV (mid-IR/FIR) 
(Dust Reprocessed)
UV targeted 
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ALPINE’s 
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Figure 1. Left: SFR density across cosmic time (figure adapted from Madau & Dickinson
(2014)). ALPINE targets galaxies in the early growth phase, a transition phase between pri-
mordial and mature galaxy formation where galaxies substantially increase their stellar mass,
dust, and metal content. Right: Fraction of flux density emitted by galaxies directly in the UV
(top shading), by UV-selected galaxies in the far-IR (middle shading), and by galaxies only
probed in blind far-IR surveys (bottom shading). Figure adapted from Bouwens et al. (2009).
between primordial (during the Epoch of Reionization at z > 4) and mature (at the peak
of cosmic SFR density at z ∼ 2− 4) galaxy formation.
To date, more than 1000 galaxies have been identified at 4 < z < 6 by photomet-
ric redshifts, color-color selections, and narrow-band observations targeting Lyα. Several
hundred galaxies have been confirmed spectroscopically. Large surveys with HST specif-
ically focus on the galaxies’ UV properties including their luminosity function, UV dust
obscuration, and morphology (e.g., Bouwens et al. 2015, Shibuya et al. 2015). Observa-
tions with Spitzer at 3 − 5µm (rest-frame optical) are used to determine robust stellar
masses and to estimate SFRs and stellar mass growth rates from optical emission lines
such as Hα (Davidzon et al. 2017, Faisst et al. 2016a). In addition, deep rest-frame UV
spectroscopy from 8-10 meter telescopes (e.g., Keck and VLT) characterize UV emission
lines (such as Lyα or He II) and provide important constraints on metallicity from the
measurement of various absorption features (Ando et al. 2007, Faisst et al. 2016b).
These large UV to optical surveys lay the foundation for a comprehensive panchromatic
study over many orders of frequencies with the newest and next-generation facilities. The
ALPINE survey with ALMA is a current example of this. The combination of ALMA’s
sensitivity and efficiency with carefully pre-selected samples from complete optical sur-
veys opens doors for the first large-sample study of dust and gas properties of galaxies
in the early growth phase at z > 4.
2. ALPINE : A Textbook Example of a Panchromatic Study
The ALMA Large Program to Investigate [C II] at Early Times is a 70-hour ALMA
cycle 5 program (#2017.1.00428.L) to carry out targeted Band-7 observations of 122
main-sequence galaxies in the early growth phase at 4 < z < 6 (Figure 1). ALPINE is a
diverse, multi-national collaboration of ∼ 45 scientists, led by the PI-team of O. LeFe`vre
(PI), A. Faisst (North America science lead), M. Be´thermin (ALMA data reduction lead),
P. Cassata, P. Capak, D. Schaerer, J. Silverman, and L. Yan. As of today (December
2018), 85% of the data has been acquired and reduced. For more information on ALPINE,
we refer to future survey papers.
Panchromatic Study of the First Galaxies 3
Spitzer
4.5
!m
3.6
!m
(H
α)
ALMA/[CII]
Full Keck/DEIMOS rest-UV spectrum
ACS/F814W
Si	II C	II Si	IV Si	IVLyα
Figure 2. Demonstration of the power of panchromatic data on a galaxy from ALPINE. Clock-
wise: [C II] emission and dust continuum from ALMA; HST imaging; multi-band SED and
Hα from Spitzer color; rest-frame UV spectrum from Keck/DEIMOS (Lyα and absorption lines).
ALPINE maximizes its efficiency and impact by building upon a carefully pre-selected
sample in the Cosmic Evolution Survey (COSMOS, Scoville et al. 2007) and the Extended
Chandra Deep Field South (E-CDFS, Giacconi et al. 2002) fields, well studied fields at UV
to near-IR wavelengths. The sample is drawn from large spectroscopic surveys undertaken
at Keck (Hasinger et al. 2018) and VLT (LeFe`vre et al. 2015), including galaxies with
diverse spectroscopic properties in rest-frame UV emission and absorption lines. This
approach leads to a complete probe of a diverse galaxy population above SFR ∼ 10 M/yr
in a stellar mass range of 9 < log(M/M) < 11. By following up UV-selected galaxies,
ALPINE probes more than 80% of the total missing flux density at these redshifts, while
blind surveys with ALMA cover the remaining less than 20% (Figure 1). In combination
with its multi-wavelength ancillary data, ALPINE is a textbook example of one of the
first large panchromatic surveys probing galaxies in the early Universe (Figure 2).
2.1. ALPINE Science in a Nutshell
ALPINE builds upon its successful small-scale pre-cursor study based on 10 galax-
ies at z ∼ 5.5 (Riechers et al. 2014, Capak et al. 2015) and reaches a similar sensi-
tivities (continuum: 50µJy or log(LFIR/L) ∼ 10.3; line: SCII∆v ∼ 0.05 Jy km/s or
log(LCII/L) ∼ 7.5) and resolution (0.5′′ − 0.7′′). Its main goal is to quantify the evolu-
tion of obscured star-formation, the gas and dust content, and gas kinematics of galaxies
in the early universe via [C II] emission and far-IR continuum measurements at rest-frame
∼ 150µm. [C II] is one of the dominant coolants, hence one of the strongest far-IR lines.
In addition the atmospheric transmission is high, making these observations favorable.
ALPINE combines several science goals and is designed to answer the following questions.
How does the total star-formation evolve at 4 < z < 6? ALPINE provides a compre-
hensive study of the total SFR density at these redshifts from UV and far-IR continuum
measurements. Independent SFRs from far-IR, [C II], and Hα (derived from Spitzer col-
4 Andreas Faisst
ors, see Faisst et al. 2016a) provide the first measurement of the SFR versus stellar mass
main-sequence on different timescales of star-formation at these redshifts.
Is [C II] a reliable SFR indicator at high-z? The prevalence of [C II] emission in high-
redshift galaxies is a promising tool to estimate SFRs of far-IR continuum faint galaxies.
ALPINE allows to calibrate this locally well established (De Looze et al. 2014) relation
at z > 4 where galaxies are more metal poor.
How dusty are galaxies in the early universe? Small-sample studies of the IRX−β rela-
tion, which relates the total dust extinction to the line-of-sight dust obscuration, suggest
diverse dust properties at z ∼ 5 (Faisst et al. 2017). ALPINE ’s large sample constrains
the diversity and studies its causes by a comprehensive analysis of its ancillary data.
How does the gas fraction evolve at z > 4? ALPINE constrains gas masses from far-
IR continuum, [C II], and dynamical mass measurements and measures gas kinematics
from [C II] profiles. It is the first study to trace the evolution of gas mass out to z = 6.
ALPINE unites current UV to far-IR facilities and will in the future build a benchmark
sample for various simulations and set the basis for follow-up observations with the James
Webb Space Telescope and other next-generation ground- and space-based facilities.
3. Conclusions
Large photometric and spectroscopic surveys at UV to near-IR wavelengths provide
a solid basis to build a full panchromatic sample over the next couple of years. Im-
portantly, these samples build on a variety of galaxies, which makes optimally planned
targeted follow-up observations with ALMA and later JWST and TMT/E-ELT efficient
in covering a significant amount of the parameter space of galaxy properties. A cur-
rent example is ALPINE, which is specifically built to extend the wavelength coverage
of a carefully chosen large spectroscopic sample with ground- and space-based multi-
wavelength photometric ancillary data. This makes it to one of the currently largest
panchromatic samples to study the formation and evolution of normal main-sequence
galaxies in the early Universe. In the future, the ALPINE sample will provide a solid
basis for follow-up observations with various next-generation facilities.
References
Ando, M., Ohta, K., Iwata, I., et al. 2007, PASJ, 59, 717
Bouwens, R. J., Illingworth, G. D., Franx, M., et al. 2009, ApJ, 705, 936
Bouwens, R. J., Illingworth, G. D., Oesch, P. A., et al. 2015, ApJ, 803, 34
Capak, P. L., Carilli, C., Jones, G., et al. 2015, Nature, 522, 455
Davidzon, I., Ilbert, O., Laigle, C., et al. 2017, A&A, 605, A70
De Looze, I., Cormier, D., Lebouteiller, V., et al. 2014, A&A, 568, A62
Faisst, A. L., Capak, P., Hsieh, B. C., et al. 2016, ApJ, 821, 122
Faisst, A. L., Capak, P. L., Davidzon, I., et al. 2016, ApJ, 822, 29
Faisst, A. L., Capak, P. L., Yan, L., et al. 2017, ApJ, 847, 21
Fo¨rster Schreiber, N. M., Shapley, A. E., Erb, D. K., et al. 2011, ApJ, 731, 65
Giacconi, R., Zirm, A., Wang, J., et al. 2002, ApJS, 139, 369
Hasinger, G., Capak, P., Salvato, M., et al. 2018, ApJ, 858, 77
Le Fe`vre, O., Tasca, L. A. M., Cassata, P., et al. 2015, A&A, 576, A79
Madau, P., & Dickinson, M. 2014, ARAA, 52, 415
Maiolino, R., Nagao, T., Grazian, A., et al. 2008, A&A, 488, 463
Riechers, D. A., Carilli, C. L., Capak, P. L., et al. 2014, ApJ, 796, 84
Scoville, N., Aussel, H., Brusa, M., et al. 2007, ApJS, 172, 1
Shibuya, T., Ouchi, M., Kubo, M., & Harikane, Y. 2016, ApJ, 821, 72


Panchromatic Study of the First Galaxies with Large ALMA Programs

Panchromatic Study of the First Galaxies with Large ALMA Programs

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