NGC 404: A rejuvenated lenticular galaxy on a merger-induced, blueward excursion into the green valley

David A. Thilker, Luciana Bianchi, David Schiminovich, Armando Gil De Paz, Mark Seibert, Barry F. Madore, Ted Wyder, R. Michael Rich, Sukyoung Yi, Tom Barlow, Tim Conrow, Karl Forster, Peter Friedman, Chris Martin, Patrick Morrissey, Susan Neff, Todd Small

Research output: Contribution to journalArticle

66 Citations (Scopus)

Abstract

We have discovered recent star formation in the outermost portion ((1-4) × R 25) of the nearby lenticular (S0) galaxy NGC 404 using Galaxy Evolution Explorer UV imaging. FUV-bright sources are strongly concentrated within the galaxy's H I ring (formed by a merger event according to del Río etal.), even though the average gas density is dynamically subcritical. Archival Hubble Space Telescope imaging reveals resolved upper main-sequence stars and conclusively demonstrates that the UV light originates from recent star formation activity. We present FUV, NUV radial surface brightness profiles, and integrated magnitudes for NGC 404. Within the ring, the average star formation rate (SFR) surface density (ΣSFR) is 2.2 × 10-5 Myr-1kpc-2. Of the total FUV flux, 70% comes from the H I ring which is forming stars at a rate of 2.5 × 10-3 M yr-1. The gas consumption timescale, assuming a constant SFR and no gas recycling, is several times the age of the universe. In the context of the UV-optical galaxy color-magnitude diagram, the presence of the star-forming H I ring places NGC 404 in the green valley separating the red and blue sequences. The rejuvenated lenticular galaxy has experienced a merger-induced, disk-building excursion away from the red sequence toward bluer colors, where it may evolve quiescently or (if appropriately triggered) experience a burst capable of placing it on the blue/star-forming sequence for up to ∼ 1 Gyr. The green valley galaxy population is heterogeneous, with most systems transitioning from blue to red but others evolving in the opposite sense due to acquisition of fresh gas through various channels.

Original languageEnglish
JournalAstrophysical Journal Letters
Volume714
Issue number1 PART 2
DOIs
Publication statusPublished - 2010 Jan 1

Fingerprint

merger
valleys
galaxies
valley
star formation rate
gas
rings
star formation
gases
blue stars
stars
recycling
color-magnitude diagram
diagram
main sequence stars
gas density
timescale
Hubble Space Telescope
rate
bursts

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Thilker, D. A., Bianchi, L., Schiminovich, D., Gil De Paz, A., Seibert, M., Madore, B. F., ... Small, T. (2010). NGC 404: A rejuvenated lenticular galaxy on a merger-induced, blueward excursion into the green valley. Astrophysical Journal Letters, 714(1 PART 2). https://doi.org/10.1088/2041-8205/714/1/L171
Thilker, David A. ; Bianchi, Luciana ; Schiminovich, David ; Gil De Paz, Armando ; Seibert, Mark ; Madore, Barry F. ; Wyder, Ted ; Rich, R. Michael ; Yi, Sukyoung ; Barlow, Tom ; Conrow, Tim ; Forster, Karl ; Friedman, Peter ; Martin, Chris ; Morrissey, Patrick ; Neff, Susan ; Small, Todd. / NGC 404 : A rejuvenated lenticular galaxy on a merger-induced, blueward excursion into the green valley. In: Astrophysical Journal Letters. 2010 ; Vol. 714, No. 1 PART 2.
@article{d4b467d142974d73bae5c5d83926d253,
title = "NGC 404: A rejuvenated lenticular galaxy on a merger-induced, blueward excursion into the green valley",
abstract = "We have discovered recent star formation in the outermost portion ((1-4) × R 25) of the nearby lenticular (S0) galaxy NGC 404 using Galaxy Evolution Explorer UV imaging. FUV-bright sources are strongly concentrated within the galaxy's H I ring (formed by a merger event according to del R{\'i}o etal.), even though the average gas density is dynamically subcritical. Archival Hubble Space Telescope imaging reveals resolved upper main-sequence stars and conclusively demonstrates that the UV light originates from recent star formation activity. We present FUV, NUV radial surface brightness profiles, and integrated magnitudes for NGC 404. Within the ring, the average star formation rate (SFR) surface density (ΣSFR) is 2.2 × 10-5 Myr-1kpc-2. Of the total FUV flux, 70{\%} comes from the H I ring which is forming stars at a rate of 2.5 × 10-3 M ⊙yr-1. The gas consumption timescale, assuming a constant SFR and no gas recycling, is several times the age of the universe. In the context of the UV-optical galaxy color-magnitude diagram, the presence of the star-forming H I ring places NGC 404 in the green valley separating the red and blue sequences. The rejuvenated lenticular galaxy has experienced a merger-induced, disk-building excursion away from the red sequence toward bluer colors, where it may evolve quiescently or (if appropriately triggered) experience a burst capable of placing it on the blue/star-forming sequence for up to ∼ 1 Gyr. The green valley galaxy population is heterogeneous, with most systems transitioning from blue to red but others evolving in the opposite sense due to acquisition of fresh gas through various channels.",
author = "Thilker, {David A.} and Luciana Bianchi and David Schiminovich and {Gil De Paz}, Armando and Mark Seibert and Madore, {Barry F.} and Ted Wyder and Rich, {R. Michael} and Sukyoung Yi and Tom Barlow and Tim Conrow and Karl Forster and Peter Friedman and Chris Martin and Patrick Morrissey and Susan Neff and Todd Small",
year = "2010",
month = "1",
day = "1",
doi = "10.1088/2041-8205/714/1/L171",
language = "English",
volume = "714",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "1 PART 2",

}

Thilker, DA, Bianchi, L, Schiminovich, D, Gil De Paz, A, Seibert, M, Madore, BF, Wyder, T, Rich, RM, Yi, S, Barlow, T, Conrow, T, Forster, K, Friedman, P, Martin, C, Morrissey, P, Neff, S & Small, T 2010, 'NGC 404: A rejuvenated lenticular galaxy on a merger-induced, blueward excursion into the green valley', Astrophysical Journal Letters, vol. 714, no. 1 PART 2. https://doi.org/10.1088/2041-8205/714/1/L171

NGC 404 : A rejuvenated lenticular galaxy on a merger-induced, blueward excursion into the green valley. / Thilker, David A.; Bianchi, Luciana; Schiminovich, David; Gil De Paz, Armando; Seibert, Mark; Madore, Barry F.; Wyder, Ted; Rich, R. Michael; Yi, Sukyoung; Barlow, Tom; Conrow, Tim; Forster, Karl; Friedman, Peter; Martin, Chris; Morrissey, Patrick; Neff, Susan; Small, Todd.

In: Astrophysical Journal Letters, Vol. 714, No. 1 PART 2, 01.01.2010.

Research output: Contribution to journalArticle

TY - JOUR

T1 - NGC 404

T2 - A rejuvenated lenticular galaxy on a merger-induced, blueward excursion into the green valley

AU - Thilker, David A.

AU - Bianchi, Luciana

AU - Schiminovich, David

AU - Gil De Paz, Armando

AU - Seibert, Mark

AU - Madore, Barry F.

AU - Wyder, Ted

AU - Rich, R. Michael

AU - Yi, Sukyoung

AU - Barlow, Tom

AU - Conrow, Tim

AU - Forster, Karl

AU - Friedman, Peter

AU - Martin, Chris

AU - Morrissey, Patrick

AU - Neff, Susan

AU - Small, Todd

PY - 2010/1/1

Y1 - 2010/1/1

N2 - We have discovered recent star formation in the outermost portion ((1-4) × R 25) of the nearby lenticular (S0) galaxy NGC 404 using Galaxy Evolution Explorer UV imaging. FUV-bright sources are strongly concentrated within the galaxy's H I ring (formed by a merger event according to del Río etal.), even though the average gas density is dynamically subcritical. Archival Hubble Space Telescope imaging reveals resolved upper main-sequence stars and conclusively demonstrates that the UV light originates from recent star formation activity. We present FUV, NUV radial surface brightness profiles, and integrated magnitudes for NGC 404. Within the ring, the average star formation rate (SFR) surface density (ΣSFR) is 2.2 × 10-5 Myr-1kpc-2. Of the total FUV flux, 70% comes from the H I ring which is forming stars at a rate of 2.5 × 10-3 M ⊙yr-1. The gas consumption timescale, assuming a constant SFR and no gas recycling, is several times the age of the universe. In the context of the UV-optical galaxy color-magnitude diagram, the presence of the star-forming H I ring places NGC 404 in the green valley separating the red and blue sequences. The rejuvenated lenticular galaxy has experienced a merger-induced, disk-building excursion away from the red sequence toward bluer colors, where it may evolve quiescently or (if appropriately triggered) experience a burst capable of placing it on the blue/star-forming sequence for up to ∼ 1 Gyr. The green valley galaxy population is heterogeneous, with most systems transitioning from blue to red but others evolving in the opposite sense due to acquisition of fresh gas through various channels.

AB - We have discovered recent star formation in the outermost portion ((1-4) × R 25) of the nearby lenticular (S0) galaxy NGC 404 using Galaxy Evolution Explorer UV imaging. FUV-bright sources are strongly concentrated within the galaxy's H I ring (formed by a merger event according to del Río etal.), even though the average gas density is dynamically subcritical. Archival Hubble Space Telescope imaging reveals resolved upper main-sequence stars and conclusively demonstrates that the UV light originates from recent star formation activity. We present FUV, NUV radial surface brightness profiles, and integrated magnitudes for NGC 404. Within the ring, the average star formation rate (SFR) surface density (ΣSFR) is 2.2 × 10-5 Myr-1kpc-2. Of the total FUV flux, 70% comes from the H I ring which is forming stars at a rate of 2.5 × 10-3 M ⊙yr-1. The gas consumption timescale, assuming a constant SFR and no gas recycling, is several times the age of the universe. In the context of the UV-optical galaxy color-magnitude diagram, the presence of the star-forming H I ring places NGC 404 in the green valley separating the red and blue sequences. The rejuvenated lenticular galaxy has experienced a merger-induced, disk-building excursion away from the red sequence toward bluer colors, where it may evolve quiescently or (if appropriately triggered) experience a burst capable of placing it on the blue/star-forming sequence for up to ∼ 1 Gyr. The green valley galaxy population is heterogeneous, with most systems transitioning from blue to red but others evolving in the opposite sense due to acquisition of fresh gas through various channels.

UR - http://www.scopus.com/inward/record.url?scp=77950930291&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77950930291&partnerID=8YFLogxK

U2 - 10.1088/2041-8205/714/1/L171

DO - 10.1088/2041-8205/714/1/L171

M3 - Article

AN - SCOPUS:77950930291

VL - 714

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

SN - 2041-8205

IS - 1 PART 2

ER -